Use the following information to answer the questions below.
Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies.
-In one type cross of black × black, the results were as follows:
9/16 black
4/16 yellow
3/16 brown
The genotype aabb must result in which of the following?