When a researcher transplanted the nucleus of an intestinal cell from a tadpole into an egg cell whose nucleus had been destroyed, the egg developed into a normal frog. This illustrates that

A) scientists can clone a human by putting one of his or her nuclei into an egg cell.
B) each cell of an organism has all the genes needed for development.
C) a nucleus that is removed from its normal location is influenced by adjoining cells.
D) the homeobox genes in a transplanted nucleus undergo mutation.
E) genes are gained during the process of differentiation.