A company uses a third-party identity provider (IdP).

AWS IAM Identity Center (formerly AWS Single Sign-On or AWS SSO)provides a single sign-on experience for accessing AWS accounts and applications by integrating with third-party identity providers (IdPs) like Microsoft Active Directory, Okta, or any SAML 2.0-compliant IdP. This service allows employees to log in once using their existing corporate credentials managed by the third-party IdP and gain access to multiple AWS accounts and services without needing separate AWS credentials.

Why other options are not suitable:

A. AWS Directory Service: Provides a managed Microsoft Active Directory, but does not directly support single sign-on integration with third-party IdPs.

B. Amazon Cognito: Primarily used for managing authentication for web and mobile apps, not for integrating third-party IdPs for AWS management access.

D. AWS Resource Access Manager (AWS RAM): Used for sharing AWS resources across accounts, not for identity and access management.