Amazon Kendra Experience Builder provides a fully managed, low-code solution for building conversational search and question-answering applications. AWS documentation states that Kendra natively supports semantic search, vector embeddings, and vector-based retrieval, making it well suited for RAG-style applications with minimal development effort.

When integrated with Amazon Bedrock, Kendra can act as the retrieval layer, handling document ingestion, indexing, embedding generation, and relevance ranking automatically. This eliminates the need to manually manage embedding models, vector databases, and search logic.

Options B and C require custom schema design, vector indexing, query logic, and operational management of PostgreSQL instances. Although pgvector supports vector search, it significantly increases development and maintenance effort. Option D is unrelated to vector search and is used only for metadata cataloging.

AWS explicitly positions Amazon Kendra as the fastest way to build enterprise-grade conversational assistants that integrate with foundation models.

Therefore, Option A is the correct and most AWS-aligned solution.

AWS Glue Data Quality provides managed, declarative data quality checks with minimal configuration. Combined with Glue crawlers, it enables automatic schema discovery and quality validation without custom code.

Option A uses native AWS services designed for this exact purpose, minimizing operational overhead. Options B and C require custom code and maintenance. Option D is not designed for data validation.

AWS documentation explicitly recommends Glue Data Quality rules for scalable, automated data quality checks in analytics pipelines.

Therefore, Option A is the correct and AWS-aligned solution.

Amazon EMR clusters consist of primary, core, and task nodes, each with a distinct role. The primary node manages the cluster, core nodes store data and run tasks, and task nodes only run tasks without storing data. AWS documentation recommends using task nodes for scaling compute capacity when workloads are compute-intensive, such as data ingestion and transformation pipelines.

To reduce processing time cost-effectively, AWS strongly advises using Spot Instances for task nodes. Spot Instances provide the same compute capacity as On-Demand Instances but at a significantly reduced cost, often up to 90% lower. Because task nodes do not store HDFS data, they can be safely interrupted without risking data loss.

Increasing the number of primary nodes is not supported by EMR and would not improve performance. Increasing core nodes affects both storage and compute and is more expensive, especially when using On-Demand Instances. Option D is therefore the least cost-effective.

AWS EMR best practices explicitly state that scaling out with Spot task nodes is the preferred way to improve performance for transient, parallel workloads such as ETL, ingestion, and feature preparation.

Therefore, Option C is the most cost-effective and AWS-recommended solution.

For cross-account Amazon S3 access, AWS requires two components:

An S3 bucket policy in the owning account (Account A) that grants access to a principal in another account

An IAM role policy in the consuming account (Account B) that allows the service to access the bucket

Amazon SageMaker training jobs assume an IAM role in the account where the job runs—in this case, Account B. Therefore, the IAM policy must be attached to the SageMaker execution role in Account B.

The S3 bucket policy must reside in Account A because bucket policies are owned and enforced by the bucket owner. This policy explicitly allows the IAM role from Account B to read the training data.

Any other combination fails either because the policy is in the wrong account or because the role is not the one used by SageMaker.

AWS documentation clearly describes this pattern as the correct way to grant cross-account access for SageMaker training jobs.

Therefore, Option B is the correct and AWS-aligned solution.

Amazon SageMaker Data Wrangler supports both direct and cataloged connections. To ensure data is always up to date, AWS recommends using cataloged connections backed by AWS Glue Data Catalog.

Cataloged connections allow Data Wrangler to reference the source systems dynamically, ensuring that each import reflects the latest data changes without manual reconfiguration. This approach supports Amazon S3, Amazon Redshift, and Snowflake and integrates securely using managed credentials.

Direct connections are point-in-time imports and do not automatically reflect schema or data updates. Glue and Lambda-based solutions introduce unnecessary complexity and operational overhead.

Therefore, using cataloged connections in Data Wrangler is the correct solution.

Scenario: The company wants to perform online validation of a new ML model on 10% of the traffic before fully deploying the model in production. The setup must have minimal operational overhead.

Why Use SageMaker Production Variants?

Built-In Traffic Splitting: Amazon SageMaker endpoints support production variants, allowing multiple models to run on a single endpoint. You can direct a percentage of incoming traffic to each variant by adjusting the variant weights.

Ease of Management: Using production variants eliminates the need for additional infrastructure like separate endpoints or custom ALB configurations.

Monitoring with CloudWatch: SageMaker automatically integrates with CloudWatch, enabling real-time monitoring of model performance and invocation metrics.

Steps to Implement:

Deploy the New Model as a Production Variant:

Update the existing SageMaker endpoint to include the new model as a production variant. This can be done via the SageMaker console, CLI, or SDK.

Example SDK Code:

import boto3

sm_client = boto3.client( ' sagemaker ' )

response = sm_client.update_endpoint_weights_and_capacities(

EndpointName= ' existing-endpoint-name ' ,

DesiredWeightsAndCapacities=[

{ ' VariantName ' : ' current-model ' , ' DesiredWeight ' : 0.9},

{ ' VariantName ' : ' new-model ' , ' DesiredWeight ' : 0.1}

]

)

Set the Variant Weight:

Assign a weight of 0.1 to the new model and 0.9 to the existing model. This ensures 10% of traffic goes to the new model while the remaining 90% continues to use the current model.

Monitor the Performance:

Use Amazon CloudWatch metrics, such as InvocationCount and ModelLatency, to monitor the traffic and performance of each variant.

Validate the Results:

Analyze the performance of the new model based on metrics like accuracy, latency, and failure rates.

Why Not the Other Options?

Option B: Setting the weight to 1 directs all traffic to the new model, which does not meet the requirement of splitting traffic for validation.

Option C: Creating a new endpoint introduces additional operational overhead for traffic routing and monitoring, which is unnecessary given SageMaker ' s built-in production variant capability.

Option D: Configuring the ALB to route traffic requires manual setup and lacks SageMaker ' s seamless variant monitoring and traffic splitting features.

Conclusion:

Using production variants with a weight of 0.1 for the new model on the existing SageMaker endpoint provides the required traffic split for online validation with minimal operational overhead.

AWS Glue is a serverless data integration service that is well-suited for creating data ingestion pipelines, especially when raw data is stored in Amazon S3. It can clean, transform, and catalog data, making it accessible for downstream ML tasks.

Amazon SageMaker Studio Classic provides a comprehensive environment for building, training, and deploying ML models. It includes built-in tools and capabilities to create efficient model deployment pipelines with minimal setup.

This combination ensures seamless integration of data ingestion and ML model deployment with minimal operational overhead.

This requirement combines asynchronous inference on large datasets with automated data quality monitoring and alerting. AWS documentation explicitly recommends Amazon SageMaker batch transform for large-scale, asynchronous inference workloads. Batch transform jobs process large datasets stored in Amazon S3 without requiring a persistent endpoint, making them cost-effective and scalable.

For data quality monitoring, Amazon SageMaker Model Monitor is the AWS-native solution. Model Monitor can be scheduled to analyze inference data, compare it against a baseline, and detect data quality issues such as missing values, schema changes, or statistical drift. When violations occur, Model Monitor emits metrics to Amazon CloudWatch, where alarms can trigger alerts.

Options A, B, and C lack ML-aware data quality monitoring capabilities. AWS Glue and Batch are not designed for model data quality analysis, and CloudTrail tracks API activity—not data quality.

AWS best practices clearly position Batch Transform + Model Monitor as the correct architecture for asynchronous inference with automated monitoring and alerting.

Therefore, Option D is the correct and AWS-verified solution.

Linear regression model whose coefficients should shrink but not become zero

Answer: L2 regularization

AWS says L2 produces smaller overall weight values and is the right fit when coefficients should be reduced without being forced to zero.

Polynomial regression model with irrelevant polynomial terms that should be eliminated

Answer: L1 regularization

AWS says L1 reduces the number of features used by pushing small weights to zero , which matches elimination of irrelevant terms.

Logistic regression model that has highly correlated features to eliminate highly redundant predictors

Answer: L1 regularization

This is the nuanced one. AWS says L2 stabilizes weights when there is high correlation between features , but because the question explicitly says eliminate highly redundant predictors , L1 is the better match since it creates sparsity and removes predictors by zeroing coefficients.

Amazon MSK Serverless provides a fully managed Apache Kafka-compatible service that automatically handles provisioning, scaling, and capacity management. AWS documentation states that MSK Serverless is designed for customers who want Kafka functionality without managing infrastructure.

Option B requires capacity planning and scaling management. Option C uses proprietary technology rather than open source. Option D requires full infrastructure management.

MSK Serverless delivers near real-time streaming with minimal operational overhead while maintaining compatibility with open-source Kafka tooling.

Therefore, Option A is the correct solution.