In the Deserts of the Southwestern United States, Rock Formations

In the deserts of the southwestern United States, rock formations made from lava flows are found scattered across the sand. The rock pocket mouse, which has dark fur, lives on the black lava rocks. The Apache pocket mouse, which has light fur, lives on the tan sand.Which of the following statements best explains how these two types of mice could have evolved from a common ancestor?

A) Individual mice changed their fur color to escape their predators.
B) Natural selection favored different fur colors in the different habitats.
C) The emigration of mice changed the gene pools in the original population.
D) The original population of mice spread out geographically to relieve overcrowding.