For corals, which of the following is necessary to maintain genetic diversity?

A. neither asexual nor sexual reproduction

B. sexual reproduction

C. asexual reproduction

D. both asexual and sexual reproduction

I think the correct answer from the choices listed above is option C. For corals, it is asexual reproduction that is necessary to maintain genetic diversity. In asexual reproduction, new clonal polyps bud off from parent polyps to expand or begin new colonies. Hope this answers the question.