A company uses an organization in AWS Organizations to manage a multi-account landing zone.

AWS recommends using AWS IAM Identity Center (formerly AWS SSO) for centralized authentication and access control across multiple accounts in an AWS Organization, especially when integrating with an external IdP.

From AWS Documentation:

“Use IAM Identity Center to provide centralized access to multiple AWS accounts or applications. You can integrate with an external IdP via SAML 2.0. Assign users permissions through permission sets that define the roles users can assume.”

(Source: AWS IAM Identity Center User Guide)

Why B and E are correct:

E enables centralized identity federation using IAM Identity Center with your external IdP.

B uses permission sets to apply least-privilege access roles to users and groups across accounts, in alignment with the principle of least privilege.

Why others are incorrect:

Option A: IAM users in each account break centralized access model and are hard to manage at scale.

Option C: Managing individual IAM roles and inline policies across accounts is not scalable.

Option D: Per-account SAML providers are redundant when using IAM Identity Center, which provides centralized federation.