Which of the following is the most effective at eradicating a system infected with a Rootkit?

Rootkits actively hide their services from the OS; they will not appear in the Services control panel because they intercept and filter OS enumeration calls to conceal themselves.

Rootkits operate at or below the kernel level, hooking system calls to conceal their presence from all OS-based utilities, including antivirus software, file explorers, and service managers. Because the infected OS itself cannot be trusted to fully remove the rootkit, the only reliable remediation is to format the drive to eliminate all infected files, perform a clean OS reinstall with current patches to close the exploited vulnerability, and change all credentials that may have been compromised.

Rootkits do not register with the Windows installer and will not appear in Add/Remove Programs; they are specifically designed to be invisible to all standard OS management interfaces.

The files belonging to a rootkit are hidden from the file system by the rootkit's own hooks, so they cannot be browsed or deleted through standard OS tools, and removing a visible shortcut would not affect the deeply embedded components.