Which Azure AD feature lets users sign in once to access multiple applications?

Single Sign-On (SSO) is the correct answer because it allows users to authenticate once and gain access to multiple independent software systems without re-entering credentials. This significantly improves user experience and reduces the overhead of managing multiple passwords. RBAC (Role-Based Access Control) is incorrect because it defines what actions a user can perform within a system, not how they authenticate across multiple systems. Conditional Access is incorrect because it enforces policies based on user, device, location, and application conditions to grant or deny access, rather than enabling single sign-on itself. MFA (Multi-Factor Authentication) is incorrect because it adds an extra layer of security during the authentication process, requiring more than one verification method, but doesn't inherently enable access to multiple applications with a single sign-in.