What policy setting in MDM prevents installation of mobile applications from unknown sources?

The policy setting that prevents the installation of mobile applications from unknown sources is centered on ensuring that the option for "Allow non-Play Store apps from unknown sources" is unchecked. This setting directly controls whether users can install applications that are not from the official Play Store on Android devices. By unchecking this option, organizations can maintain a higher level of security, as it restricts the installation of potentially harmful applications that may come from unverified sources.

While other options may involve application management or oversight, adjusting the setting to prohibit installations from unknown sources specifically addresses the key concern of unauthorized app installations, making it a crucial aspect of mobile device management (MDM) security protocols.