Which AWS service monitors AWS accounts for security threats?

Explanations:

Amazon GuardDuty is a threat detection service that continuously monitors AWS accounts and workloads for malicious activity and unauthorized behavior.

AWS Secrets Manager is used for managing secrets, such as API keys and passwords, and does not monitor accounts for security threats.

Amazon Cognito provides user authentication and management for applications but does not offer security threat monitoring for AWS accounts.

AWS Certificate Manager (ACM) manages SSL/TLS certificates for securing websites and applications, but it does not monitor AWS accounts for security threats.