Which malware is known for its ability to replicate and spread independently?

The correct choice identifies a worm as malware that can independently replicate and spread without needing to attach itself to a host file or rely on human intervention. Unlike other types of malware, such as Trojan horses, ransomware, or rootkits, worms have the distinct capability to propagate automatically through networks. They exploit vulnerabilities in software or operating systems to move from one machine to another, often causing widespread harm and disruption as they replicate themselves.

A Trojan horse, for example, disguises itself as legitimate software but requires user action to install, and it cannot spread on its own. Ransomware, on the other hand, encrypts files and demands a ransom for decryption but also cannot replicate without human action. Lastly, a rootkit is designed to enable continued privileged access to a computer while hiding its presence but does not possess the ability to replicate or spread independently. Therefore, the key characteristic that distinguishes worms is their independent replication and spreading mechanism, cementing their classification as a unique type of malware.