Answer:
The correct answer is "selection favors multiple distinct trait values, and similar individuals tend to mate with each other".
Explanation:
A population with a bimodal distribution are groups of organisms with two major traits or "modes", with practically equal amounts of individuals with these two modes. This type of distributions indicate that the population is not homogenous and that more than one trait is favored in the given circumstances. A bimodal distribution is most likely to evolve when selection favors multiple distinct trait values, and similar individuals tend to mate with each other. In this case natural selection favors more than one value, and due to the individuals with one value tend to mate to each other, only two major traits are favored in the population.