An administrator wishes to prevent users from accessing unattended computers in other departments. Which of the following would BEST accomplish this?

Roaming profiles allow users to access their personal settings from any computer but do not prevent other users from accessing an unattended, already-logged-in workstation.

Event monitoring is a detective control that records login events after the fact but does not prevent unauthorized access from occurring at unattended machines.

Enforcing a password-protected screensaver with a short inactivity timeout (such as five minutes) automatically locks the workstation session when a user walks away, requiring re-authentication to resume. This directly addresses the threat of unauthorized access to unattended computers across departments without requiring any user action, making it an effective preventive control.

Shared departmental logins reduce individual accountability and create additional security vulnerabilities, making this the least secure option rather than a solution.