Which of the following statements correctly describes Single Sign-On (SSO)?

• A. Per-service login
• B. No login required
• C. Login once for multiple services
• D. Requires multiple logins

Answer: (C)

Single Sign-On lets a user prove their identity once to a central authority and then access multiple services without re-entering credentials for each one. Because the services trust that central identity provider, a single login grants access to all the connected systems during the session. That makes the statement “Login once for multiple services” the best description. Logging in per service would require separate authentications, while no login would leave you without any trusted proof of identity, and requiring multiple logins contradicts the core idea of SSO. In practice, SSO often uses tokens or tickets issued by a central identity provider that the various services accept to establish access, reducing credential prompts and simplifying user experience while centralizing authentication controls.