Which of the following technologies can self-replicate?

The ability to self-replicate is a defining characteristic of computer worms. Unlike other types of malicious software, worms can independently propagate themselves across networks without needing to attach to an existing program or file. This self-replication allows them to spread quickly and often leads to significant disruption and damage to systems.

In contrast, while spyware, viruses, and adware can have harmful effects, they do not possess the same autonomous replication capabilities. For instance, viruses require host programs to execute and replicate, and they spread when users unknowingly share the infected software. Spyware primarily focuses on gathering information without user consent, and adware serves advertising purposes, typically in exchange for free software, but neither of these types replicates themselves in the manner that worms do. Therefore, the characteristic of self-replication is unique to computer worms, making it the correct answer.