Humans, crocodiles, bats, whales, and birds have similar limb bones. What do these similarities suggest?

A.
Humans, bats, and crocodiles share an ancestor with whales but not with birds.

B.
Humans, crocodiles, bats, whales, and birds evolved from a common ancestor.

C. A similar limb structure evolved in each species independently and by chance.

D.
The common ancestor of a human and a bird was a whale.