What distinguishes a worm from a virus in terms of malware propagation?

A worm is defined by its ability to self-replicate and to propagate independently across networks without requiring a host program to attach itself to. This means that worms can spread automatically from one device to another, often exploiting vulnerabilities in network protocols, which allows them to travel rapidly and widely across systems. Unlike a virus, which typically attaches itself to an executable file or program and relies on human action—like opening a file—to spread, a worm operates autonomously.

This independence is key in understanding how worms can create significant disruptions and propagate swiftly compared to viruses, which often depend on user interaction for their propagation. Therefore, option B correctly identifies the fundamental characteristic that sets a worm apart from a virus in terms of malware propagation.