Which malware typically requires user action to be activated?

The correct choice is Trojan, as this type of malware generally requires some form of user interaction to execute. Trojans often disguise themselves as legitimate software or are embedded within seemingly harmless applications, enticing users to download and run them. Once activated by the user, Trojans can lead to unauthorized access, data theft, or other harmful actions on the system.

In contrast, other types of malware can operate automatically without user intervention. For example, ransomware can encrypt files in the background once it is installed, while worms replicate and spread through networks or the internet autonomously. Spyware typically functions stealthily to gather information without explicit user actions but can be inadvertently installed when users interact with malicious links or attachments. Understanding the different activation methods is crucial for developing effective defenses against these threats.