Which of the following is BEST to do immediately after installing an OS on a new machine in order to mitigate OS vulnerabilities?

Disabling system users might cause system instability or prevent essential services from running, as many system users are crucial for OS functionality.

While important, antivirus software primarily protects against malware and known threats, whereas patching addresses the underlying OS vulnerabilities themselves.

Enabling the firewall is a good security practice but does not mitigate existing OS vulnerabilities; it controls network traffic and inbound/outbound connections.

Installing patches (updates) immediately after OS installation addresses known security vulnerabilities and bugs that existed at the time of the OS release, significantly reducing the attack surface. This process ensures the system is brought up to the latest secure state as defined by the OS vendor.