Which of the following threats is a combination of worm, virus, and Trojan horse characteristics?

Spyware is a specific malware category designed to covertly collect user information and activity, not a combination of worm, virus, and Trojan behaviors.

Heuristic describes a malware detection technique used by antivirus engines to identify unknown threats by behavior or code patterns, not a classification of threat type.

A blended threat merges the self-replication of worms, the file-infecting behavior of viruses, and the deceptive payload delivery of Trojans into one malware instance. This multi-vector combination allows it to spread automatically across networks, infect files, and execute malicious payloads simultaneously. The term specifically describes this hybrid approach, distinguishing it from single-category malware.

Rootkits are malware designed specifically to hide the presence of other malicious software or unauthorized system modifications, not a blend of worm, virus, and Trojan characteristics.