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?
选项：

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.