Unified access to external systems for users.

• A. Service Provider (SP)
• B. Federated Access
• C. User
• D. Information Sharing

Answer: (B)

Unified access to external systems for users hinges on authentication across organizational boundaries. Federated access is the mechanism that makes this seamless by letting trusted domains establish a relationship with a common identity provider to assert user identities to external service providers. The identity provider handles the login, and the service provider trusts that assertion to grant access, enabling single sign-on without creating separate accounts for each system. This typically uses standards like SAML, OAuth, or OpenID Connect to exchange identity and authorization information. The service provider is the external system that provides the resource, and the user is the person trying to access it, but federated access is what links them across domains. Information sharing involves exchanging data, not necessarily enabling cross-domain authentication or access control.