Key deer, a subspecies of white-tailed deer, are only found on a few islands in the Florida Keys. They are tiny deer that weigh 45 to 65 pounds, which is very small compared to the 130- to 300-pound white-tailed deer that are found on the North American mainland. Which of the following conditions most likely resulted in the small size of the Key deer?
a. Human influence caused increases in Key deer populations that improved genetic variation.
b. Limited food and water resources favored the survival of smaller deer.
c. Limited size variations of deer that migrated to the islands resulted in smaller deer.
d. Overproduction of offspring on the mainland led to migration of small, less successful deer to the islands.