Which type of malware disguises itself as legitimate software but has malicious intent once installed?

A Trojan horse is malware that appears to be a legitimate program but carries malicious operations under the hood. Users often unknowingly install Trojans, which then allow unauthorized access or cause harm, such as data theft or system compromise. Why Other Options are Wrong: a) A virus is a self-replicating program but does not disguise itself as legitimate software. b) Worms spread through networks but do not disguise themselves like Trojans. d) Spyware collects data secretly but is not disguised as legitimate software. e) Ransomware locks users out of their system or files but does not disguise itself as legitimate software.