Which of the following is a virus that is capable of spreading from one computer to another on a network?

Spyware (spy bot) is designed to covertly collect user data and transmit it to a third party, but it does not self-replicate or spread autonomously across a network.

A Trojan disguises itself as legitimate software to trick users into executing it, but it relies on user interaction to install and does not self-propagate across a network.

A rootkit is designed to conceal itself and provide persistent privileged access to a system, but it does not have the self-replicating, network-spreading capability that defines a worm.

Unlike traditional viruses that must attach to a host file, a worm is a standalone malicious program that exploits network vulnerabilities or open shares to copy itself from system to system automatically. Worms can propagate rapidly across an entire network without any user action, making them uniquely dangerous in networked environments. This self-propagating behavior across a network is the defining characteristic that distinguishes worms from other malware types.