In poodles, black is dominant to white. A black poodle is crossed with a white poodle. In a litter of four, all of the puppies are black. What is the best conclusion（）

A. The black poodle is probably homozygous

B. The black poodle is definitely homozygous

C. The black poodle is definitely heterozygous

D. The black poodle is probably heterozygous