Which service helps monitor resource utilization and performance?

Correct answer: Amazon CloudWatch

Option D is correct because Amazon CloudWatch is AWS's native monitoring and observability service that collects and tracks metrics, log files, and events, providing dashboards, alarms, and automated actions based on resource utilization and performance data for virtually every AWS service. Option A is incorrect because AWS Config is a configuration compliance and change tracking service that records resource configurations over time for auditing and governance purposes, not a performance metrics monitoring service. Option B is incorrect because Amazon Inspector is an automated vulnerability assessment service that scans EC2 instances and container images for software vulnerabilities and unintended network exposure, which is a security service rather than a resource utilization monitor. Option C is incorrect because AWS CloudTrail records API call history and user activity for auditing and compliance purposes, capturing who did what and when, rather than tracking CPU, memory, or performance metrics.