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

Explanations:

AWS CloudTrail is the service that enables users to monitor, log, and audit API activity across their AWS accounts, providing visibility into user actions.

Amazon Inspector is a security assessment service that helps improve the security and compliance of applications deployed on AWS, but it does not audit API activity.

AWS WAF (Web Application Firewall) protects applications from web attacks but does not provide auditing of API activity across AWS accounts.

AWS Config provides resource configuration tracking and compliance monitoring, but it does not specifically audit API activity like AWS CloudTrail.