The correct answer is D. single sign-on (SSO). Microsoft Entra single sign-on lets users sign in once with one set of credentials and then access assigned applications without signing in again. In this scenario, users authenticate to App1 automatically by using Microsoft Entra credentials, so the app is relying on the tenant identity provider rather than requiring separate app credentials. Multifactor authentication is an additional verification step, not the automatic reuse of an authenticated session. Password synchronization synchronizes password hashes between identity stores, and pass-through authentication validates credentials against on-premises Active Directory. Neither describes the user experience shown here. The key wording is “without manually entering their credentials,” which maps directly to SSO.