The correct answer is B because Amazon CloudWatch provides monitoring capabilities that include tracking usage metrics for Amazon Comprehend endpoints, such as invocation counts. You can configure CloudWatch to collect these metrics and create custom dashboards or alarms to report when an endpoint has zero usage over a period (e.g., 15 days).

From AWS documentation:

" Amazon CloudWatch enables you to collect and track metrics for Comprehend endpoints, create alarms, and automatically react to changes in your AWS resources. "

This allows automated reporting and alerting for underused or idle endpoints.

Explanation of other options:

A. AWS Trusted Advisor focuses on general AWS resource optimization, security, and limits but does not track endpoint usage.

C. AWS CloudTrail tracks API calls but does not provide time-based monitoring or usage analysis over time.

D. AWS Config is used to track configuration changes and compliance, not endpoint usage metrics.

Referenced AWS AI/ML Documents and Study Guides:

Amazon CloudWatch Metrics for Amazon Comprehend

AWS Certified Machine Learning Specialty Guide – Monitoring and Logging Section

AWS Cloud Operations Guide – Resource Utilization Monitoring