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

The type of malware designed to replicate itself and spread to other systems is a worm. Unlike viruses, which attach themselves to software or files and require user action to spread, worms can autonomously propagate across networks without needing a host program. They exploit vulnerabilities in operating systems or applications to infect new devices, making them particularly harmful as they can cause extensive damage in a short period of time by consuming bandwidth and system resources as they spread.

In the context of the other choices, spyware is primarily focused on gathering user information without consent, ransomware encrypts files and demands payment to restore access, and adware typically generates unwanted advertisements usually for monetization rather than spreading to other systems. Each of these types of malware has distinct characteristics and purposes that differentiate them from worms.