Answer: A
Explanation:
While most of (if not, all of) viruses immediately self-replicate and spread around, a trojan horse does not. Like its name suggests, a Trojan Horse is a malicious software that disguises as a software that gets activated once downloaded and opened. Trojan horses must be spread by humans so they can be activated to do things such as steal sensitive information, giving the attacker unauthorized access to your computer, or distributing  system information online.
