【单选题】A group of mice was released into a large field to which no other mice had access. Immediately after the release, a representative sample of the mice was captured, and the fur color of each individual...
A.
The allele for gray fur color is unstable, and over twenty years most of those alleles mutated to become alleles for black fur.
B.
The field was composed primarily of light-colored soil and little vegetation, affording gray mice protection from predators.
C.
Sexual selection led to increased mating frequency of black and brown versus gray and brown.
D.
The gray mice were hardest to capture and so were underrepresented in the twenty-year sample.