Which AWS service helps users audit API activity across their AWS account?

Explanations:

AWS CloudTrail is specifically designed to log, monitor, and retain account activity related to actions taken on AWS infrastructure, including API calls made on AWS services. It helps in auditing and compliance by providing detailed event history.

Amazon Inspector is a security assessment service that helps improve the security and compliance of applications deployed on AWS. It focuses on identifying vulnerabilities and deviations from best practices but does not audit API activity.

AWS WAF (Web Application Firewall) is a service designed to protect web applications from common web exploits that could affect application availability, compromise security, or consume excessive resources. It does not track or audit API activity.

AWS Config is a service that enables users to assess, audit, and evaluate the configurations of AWS resources. While it monitors configuration changes, it does not specifically log API activity.