What is the difference between a virus and a trojan in cybersecurity terms?

• A. A trojan disguises itself as legitimate software to trick users.
• B. A virus self-replicates and attaches to files; a trojan disguises itself as legitimate software to trick users.
• C. A virus runs in the cloud while a trojan runs on devices.
• D. A virus is always harmful; a trojan is always harmless.

Answer: (B)

In cybersecurity, the key distinction is how each type of malware propagates or deceives. A virus is designed to replicate and spread by attaching itself to legitimate files or programs, so whenever those files are shared or executed, the virus copies itself. A trojan hides inside something that appears trustworthy—like a normal program or download—so a user is tricked into running it, and once opened, it carries out malicious actions. This combination is why the best description says a virus self-replicates and attaches to files, while a trojan disguises itself as legitimate software to trick users into executing it. The other options miss important aspects: one only mentions disguise without replication, another wrongly implies cloud-based vs device-based operation, and another wrongly claims trojans are harmless.