Which of the following is a characteristic of a virus?

A virus is a type of malicious software that requires a host file to replicate and execute its payload. This means that it attaches itself to legitimate programs or files, enabling it to spread when those programs or files are shared or executed. The replication process is dependent on the host file, which is why it cannot operate independently.

In the context of computer security, understanding that viruses function in conjunction with host files is crucial for developing effective antivirus strategies and maintaining safe computing environments. This distinction is fundamental to the classification of malware, as it differentiates viruses from other types of malware that might not require a host, such as worms, which can propagate independently over networks.