Which type of malware is designed to replicate itself and spread to other computers?

The correct choice describes a type of malware that is specifically engineered to replicate and propagate independently across systems. A worm can spread through networks without needing to attach itself to a host program or file, which distinguishes it from other types of malware.

In contrast, spyware is designed to gather information about a user or organization without their consent, primarily for the purpose of stealing sensitive data. Trojans, or Trojan horses, masquerade as legitimate software to trick users into executing them, enabling malicious actions—but they do not inherently replicate or spread on their own. Ransomware encrypts files on a victim's machine and demands ransom for decryption, but again lacks the self-replicating characteristics that define a worm.

Thus, the defining feature of a worm is its ability to autonomously replicate and spread across networks, making it the correct answer to the question.