Answer:
A - A Trojan horse.
Explanation:
As the exercise briefly states, a trojan horse is a program in which malicious code is hidden inside a seemingly harmless program. It's named after the mythical siege of Troy, where a giant horse was created to hide soldiers in it and then left in the doors of Troy, as a "parting gift" from the greek attackers. Therefore, this virus hides a malicious code or program inside one that seems harmless or legitimate, potentially tricking a user to load, download or execute the program.
