What should the SysOps administrator do to meet these requirements?

Explanations:

Amazon Cognito is primarily designed for building applications with user sign-up and sign-in functionalities, and while it can integrate with a third-party IdP, it does not provide a centralized management solution for user access and permissions across multiple AWS accounts in the context of AWS Organizations.

AWS Single Sign-On (SSO) is specifically designed for centrally managing access to multiple AWS accounts and applications. It can be easily integrated with a third-party SAML 2.0 IdP, allowing users to access AWS accounts and services using their existing corporate credentials while ensuring centralized management of permissions through AWS Organizations.

Federating a third-party IdP with AWS Identity and Access Management (IAM) for each AWS account would involve complex management of multiple IAM roles and policies across all accounts. This solution is not efficient for centralized user access management, especially in a multi-account architecture.

AWS Organizations does not directly support the integration of a third-party IdP. While it manages multiple accounts, it does not handle user access and permissions natively, thus requiring a solution like AWS SSO for effective integration with SAML 2.0 IdPs.