A population of caterpillars feeds on the leaves of trees in a forest and is in turn food for birds that eat them off the tree leaves. Given this information, which adaptation would be most likely to evolve?

A) Caterpillars would evolve to a larger size.
B) Caterpillars would evolve to eat the bark as well as the leaves.
C) Birds would evolve to eat more types of insects.
D) Caterpillars would evolve to a color that matched the leaves they eat.