What operation is used to retrieve a credential report for an AWS account?

The operation used to retrieve a credential report for an AWS account is GetCredentialReport. This operation allows users to generate a report that contains details about all of the IAM users in the account, including their access key status, password status, and the last time credentials were used.

Using this operation is essential for assessing the security posture of an AWS account, as it helps identify which IAM users have permissions and how those permissions are being utilized. This visibility is crucial for ensuring compliance with security policies and best practices within AWS environments.

The other options do not accurately represent the API call required for this task. They either use incorrect terminology or do not correlate with the AWS Identity and Access Management (IAM) service's naming conventions.