What type of malware is designed to replicate itself and spread to other machines?

The correct choice is a type of malware known as a virus. A virus is specifically designed to replicate itself and attach to other files or programs on a computer. When a virus-infected file is executed, it can spread to other files and systems, often without the user's knowledge. Viruses often require a host program to execute, allowing them to propagate and potentially cause harm by corrupting data or degrading system performance.

Other types of malware serve different purposes and do not have the same self-replicating capabilities. For instance, spyware is intended to gather user information without their consent, focusing on stealthily collecting data rather than self-replication. Ransomware encrypts files on a victim's system and demands payment for their release, but it does not replicate itself independently. Adware is designed to deliver advertisements to users but does not inherently replicate or spread like a virus does. Thus, the defining characteristic of a virus is its ability to self-replicate and disseminate across systems, making it the accurate selection in this context.