Answer:
A. simple
Explanation:
Asexual reproduction is mainly used by bacteria or small organisms that are too simple to have created a mechanism for sexual reproduction. The advantage of sexual reproduction is the recombination--why do you think you're not an exact copy of your parent? That's because they didn't have you via asexual reproduction.
Why not B: This is the opposite.
Why not C: This isn't necessarily a requisite condition; many bacteria do not live underwater.
Why not D: This is certainly wrong. Bacteria are not extinct, and not looking to be so anytime soon.
