Which of the following statements best explains differences between the finches?
A. Some finches were born with beaks that allowed them to have better access to different sources of food. These finches reproduced and passed on their genes.
B. The beaks of the finches changed so all of the finches could eat the same types of food.
C. The beaks of the finches changed as the species of finches migrated to the same island.
D. The beaks of the finches changed as the finches' body sizes changed.