You Are Studying Populations of a Certain Species of Frog

You are studying populations of a certain species of frog in two ponds five kilometers apart. There are no other ponds in the area. In pond A all the frogs are small and have a few black spots on them. In pond B most of the frogs are large and lack spots but a few are small without spots and a few are large with spots. Which of the following is the most likely cause of the genetic diversity seen in pond B?

A) The small frogs and spotted frogs in pond B are mutations.
B) Pond A frogs resulted from individuals migrating from pond B.
C) The small frogs and spotted frogs in pond B probably are the result of some frogs migrating from pond A to pond B.
D) Meiosis generated more genetic diversity in pond B than in pond A.