In laborador retrievers, pigment color is influenced by two genes. Gene A determines the type of pigment produced and gene B affects whether the pigment gets deposited in the hair shaft. If two heterozygous black laborator retrievers were crossed and offspring were produced in a ratio of 9 black dogs to 3 brown dogs to 4 yellow dogs, what are the genotypes of the offspring?

AaBb, AABb, AaBB, AABB, Aabb, aaBb, AAbb, aaBB, aabb.

Explanation:

Gene A conditions pigment type.

Gene B determines whether the pigment of A will be deposited.

Heterozygous black individuals will have the genotype AaBb.

Two heterozygous black individuals were crossed:

AaBb   x   AaBb

Progeny:

4 AaBb - Black

2 AABb - Black

2 AaBB - Black

1 AABB - Black

2 Aabb - yellow

2 aaBb - yellow

1 AAbb - brown

1 aaBB - brown

1 aabb - brown

Hence, the genotypes of the offspring are:

AaBb, AABb, AaBB, AABB, Aabb, aaBb, AAbb, aaBB, aabb.

See the attached image for the Punnet's square result of the cross.

your answer should be c) enjoy!