In rats, the genes B and D control fur color as follows: B_dd rats have black fur, bbD_ have yellow fur, B_D_ have brown fur, and bbdd rats have cream-colored fur. If a pure-breeding brown rat and a pure-breeding cream-colored rat mate to produce an F1, and F1 are allowed to interbreed to produce an F2, what is the expected phenotypic distribution of the brown fur color rat offspring