The correct answer is: A. are legitimate programs that allow unauthorized access.
A Trojan horse is a type of malware that disguises itself as a legitimate program in order to trick users into installing it on their computers. Once installed, a Trojan horse can give the attacker access to the user’s computer, steal their data, or even take control of their computer.
Option B is incorrect because Trojan horses are designed to work. They are often used to steal data, install other malware, or take control of a computer.
Option C is incorrect because Trojan horses are not always hidden. Some Trojan horses are designed to be hidden from the user, but others are not.
Option D is incorrect because Trojan horses are not always immediately discovered. Some Trojan horses are designed to be difficult to detect, while others are not.
Option E is incorrect because Trojan horses are a type of malware. Malware is a term used to describe malicious software that is designed to harm computers or computer systems.