In Labrador Retrievers, Black Coat Color Is Dominant to Brown

Multiple Choice

In Labrador retrievers, black coat color is dominant to brown. Suppose that a black Lab is mated with a brown one and the offspring are four black puppies and one brown puppy. What can you conclude about the genotype of the black parent?

A) The genotype must be BB.
B) The genotype must be bb.
C) The genotype must be Bb.
D) The genotype could be either BB or Bb.
E) The genotype cannot be determined from these data.