If there are multiple applications authenticated against a single identity store, which technology solution will simplify access to all applications?

RADIUS is a network access authentication protocol primarily used for VPN and network device access - it does not provide a unified token-based mechanism for simplifying access across multiple web or enterprise applications.

Single Sign-On (SSO) allows a user to authenticate once against the identity store and then gain access to all integrated applications without re-entering credentials. It leverages the shared identity store to issue tokens or assertions (such as SAML or OAuth) that each application trusts. This directly addresses the requirement of simplifying access when multiple applications share one authentication backend.

Multifactor authentication adds additional verification steps to the login process, increasing security but making access more complex rather than simpler for the user.

LDAP is a directory access protocol used as the identity store itself - it stores user credentials but does not on its own provide a mechanism for users to access multiple applications with a single authentication event.