Viruses and worms primarily differ in their method of what?

Viruses and worms primarily differ in their method of propagation and spreading. A virus attaches itself to a host file or program and typically requires human action, such as opening a file or running a program, to activate and spread. Once activated, it can replicate itself and infect other files on the same system.

On the other hand, a worm is designed to spread across networks without any human intervention. It exploits vulnerabilities in operating systems or applications to replicate itself and can move from one machine to another autonomously by sending copies of itself over a network. This fundamental difference in how they propagate illustrates why the correct answer focuses on their distinct methods of spreading.

While other options touch on aspects such as installation, targeted attacks, and detection, they do not capture the key differentiator in propagation, which is central to understanding how viruses and worms operate in network environments.