The Fact That All Modern Breeds of Dog Stem from Wild

The fact that all modern breeds of dog stem from wild wolves is evidence that

A) selection can use abundant hidden variation to move a population beyond its initial range of variation.
B) domestication of dogs involved a great deal of selection that whittled down the previously large diversity of wolves into the narrow range we call "dogs."
C) domestication of dogs involved a weakening of selection, and the result is a random range of dogs.
D) since dogs easily revert to wolf state if allowed to breed freely, dogs are mainly a cultural construct and are not genetically well defined.