A Trojan horse is a type of malware that disguises itself as a legitimate or harmless program so that a user is tricked into running it voluntarily.

Once the user executes it, its main purpose is to steal or delete files and create a backdoor for hackers, giving an attacker covert, unauthorised remote access to the compromised system.

Through that backdoor the attacker can exfiltrate data, damage files, or install further malicious tools while remaining hidden.

Unlike a worm, a Trojan does not replicate itself; it depends entirely on deception to get installed, which is why self-copying options do not describe it.

Intercepting traffic by flooding communication channels and blocking traffic by overwhelming servers both describe denial-of-service style attacks, which are not the function of a Trojan.

Silently copying itself to other systems by exploiting network vulnerabilities describes a worm, which spreads on its own without user action.

Therefore the defining behaviour of a Trojan — data theft or destruction plus a hidden backdoor — makes the correct answer To steal or delete files and create a backdoor for hackers.