Active is the term used to describe whether a verb is active or passive.

Voice is the term used to describe whether a verb is active or passive. In other words, when the subject of the verb is doing the action of the verb example:"The dog bit the postman." the verb is said to be in the active voice. So, the voice of a verb tells us whether the subject is acting or being acted upon.

Explanation:

answer: b (host)

viruses use the cells of living organisms to reproduce. the cell which is used by virus is called as "host cell". it is a living cell in which virus multiplies, example bacteria, plant or an animal cell.

in this, the virus is a parasite, which uses host cell for its benefit (reproduction) by using the cell machinary of host cell.