C: The biodiversity of aphids will increase is the correct answer.
Sexual reproduction of aphids involves the fusion of gametes from two different parents, which results in genetic diversity in the offspring. This genetic diversity can lead to improved adaptation to changing environmental conditions and increased resistance to parasites and diseases. This is an advantage of sexual reproduction in aphids, as it increases the biodiversity of the population, allowing for greater genetic variation, which can help improve the chances of survival of the species.