Which statement best explains the change over the 10 year period?

more than likely the answer is going to be D by the way the photo looks

A. The number of emigrants increased.

Explanation:

Emigration is the movement of individuals of a population from their habitat to another place. The image on left shows more number of organisms than the image on right. During the span of 10 years, increased emigration reduced the population size of the given species. Increase in carrying capacity, immigration and birth rate would have increased the population size, rather than reducing it.