An administrator needs a data a format that is support authentication against an external security domain. The data format must format support SSO. Which data format should the administrator choose?

AAA (Authentication, Authorization, and Accounting) is a security framework and architectural concept, not a data format, and does not natively support cross-domain SSO.

Kerberos is a network authentication protocol using tickets within a single domain or tightly coupled realms - it is not a data format and is not designed for federated cross-domain SSO in web contexts.

SAML is an XML-based open standard specifically designed to exchange authentication and authorization data between an identity provider (IdP) and a service provider (SP) across different security domains. It natively supports SSO by allowing users to authenticate once at the IdP and access multiple services without re-authenticating, making it the purpose-built format for this use case.

EAP (Extensible Authentication Protocol) is a framework used for network access authentication (e.g., Wi-Fi, 802.1X) and does not provide a data format for cross-domain federated SSO.