The diagram shows the leg bones of a (Left -> Right): Orangutan, dog, pig, cow, tapir, and horse. Most of the animals have the same bones, although some are shaped differently and placed in different positions.

What does this suggest about mammals?
A) That they shared a common ancestor.
B) That mammals are evolving to become more and more like one another.
C) That they developed their bone structure independently of one another.
D) That the shape of the bones has less to do with the environment pressures on the animal, and more to do with what their relatives are.