Umm so this question is throwing me a little. C makes some sense to me, as if there is direct competition, being able to practically duplicate can become useful. A doesn't make sense to me because if there is a decrease in resources, cloning isn't an advantage because there is no variation and therefore no members in the population that could utilize other resources and survive. I don't see how, when being seperated (B), asexual reproduction is very advantageous, as I guess a bigger population could allow the seperated organisms to join together again but that's not much of an advantage. D.... I mean if predation is lowered I GUESS being able to make exact copies of the same organism is a kind of advantage...I'm not 100% sure but I'm leaning towards C, though D may sense too. I hope I can help a little, at least to narrow down some choices. Have a good one!