Starting from the wild mustard Brassica oleracea, breeders have created the strains known as brussels sprouts, broccoli, kale, and cabbage. Which of the following statements is supported by this observation?

A) In this species, there is enough heritable variation to create a variety of features.
B) Natural selection has not occurred very frequently in the wild populations.
C) Heritable variation is low-otherwise the wild strain would have different characteristics.
D) In this species, most of the variation present is due to differences in soil, nutrition, amount of sunlight, or other aspects of the environment.