Final answer:
The correct answer is a) Worm. Worms are a type of malware that can spread without any user interaction, automatically replicating and spreading through computer networks.
Step-by-step explanation:
The correct answer is a) Worm. Worms are a type of malware that can spread without any user interaction. Unlike Trojans, adware, and spyware which often require some form of user action to spread, worms can automatically replicate and spread through computer networks, exploiting vulnerabilities in systems to infect other devices.
For example, the ILOVEYOU worm that spread in 2000 was transmitted through email and could automatically send itself to all contacts in the infected user's address book, spreading rapidly across the internet.
Keywords: worm, malware, spread, user interaction, Trojans, adware, spyware