Farmer Carroll breeds his black-colored dog and his golden-colored dog every spring to sell the puppies. Golden color is recessive to black. The most recent litter of puppies included 4 black and 4 golden. What most likely is the genotype of the black dog?

Bb

Explanation:

If you use "b" to represent golden allele and "B" to represent the black allele, then crossing a Bb and bb dog will result in a 50/50 chance of they offspring being black or golden. Since half of the litter is black and the other half is golden, the black colored dog has a Bb genotype.