Which of the following should be disabled to prevent malware installation?

Disabling software auto-run and auto-play is crucial for preventing malware installation because these features automatically execute programs from removable media, such as USB drives and CDs, without user intervention. This automatic execution can lead to the seamless installation of malicious software when a user inadvertently connects an infected device to their system. By turning off these features, users must explicitly choose to run programs, thereby providing a safeguard against accidentally executing harmful software that could compromise the system.

The other options, while they relate to security practices, do not directly mitigate the risk of malware installation in the same way. Manual updates, for instance, are essential for ensuring that software is patched against vulnerabilities, but disabling them would leave the software more exposed to threats. Firewall alerts are important for monitoring potentially suspicious activities; disabling them could hinder a user's ability to respond to security threats effectively. Finally, network monitoring plays a key role in detecting unusual or unauthorized activities on a network, and disabling it would limit awareness of potential security breaches. Therefore, focusing specifically on preventing unauthorized execution of programs, disabling auto-run and auto-play is the most effective measure in this context.