The flu and common cold is caused by a virus.
This justifies what answer for what question? Q & A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
A virus causes the flu and the common what?
Options:
- cold
- disease
- infection
- mutate
- make person sick
cold