Answer:
B. a cell
Step-by-step explanation:
Like their biological counterparts, computer viruses can spread rapidly and self-replicate systematically. They also mimic living viruses in the way they must adapt through mutation to the development of resistance within a system: the author of a computer virus must upgrade his creation in order to overcome the resistance (antiviral programs) or to take advantage of new weakness or loophole within the system.
Computer viruses also act like biological virus in the way they can be set off: they can be virulent from the outset of the infection or the can be activated by a specific event (logic bomb). But computer viruses can also be triggered at a specific time (time bomb). Most viruses act innocuous towards a system until their specific condition is met.