Which Windows feature alerts users to potential security issues on their computer?

The Action Center is the correct answer because it serves as a centralized location for messages and alerts related to security, maintenance, and system settings on Windows computers. It informs users about potential security issues, such as outdated antivirus definitions, critical Windows updates, or when certain security settings need to be configured or adjusted. This feature helps users maintain the security of their systems by keeping them informed about any issues that might compromise their computer's safety.

Other features mentioned, while useful, serve different purposes. For example, Windows Defender focuses specifically on providing antivirus and threat protection. Task Manager is primarily used for monitoring system performance and managing running applications. Device Manager allows users to view and manage hardware devices connected to their system. None of these features provide comprehensive alerts related to overall security issues like the Action Center does.