Considerably More Phenotypic Variation Exists in Domesticated Varieties of Species

Considerably more phenotypic variation exists in domesticated varieties of species like dogs and cabbages than exists in non-domesticated species like lions and maple trees. Which one of the following statements best explains why this is true?

A) There is no selection and mating is random under domestication.
B) During domestication, very high rates of mutation are induced.
C) Genetic drift is important because domestication involves small populations.
D) Many domesticated varieties would not survive in the natural world.
E) Domesticated species exhibit "hybrid vigor" (heterosis) .