A black guinea pig crossed with an albino guinea pig produced 12 black offspring. When the albino was crossed with a second black animal, 6 blacks and 6 albinos were obtained. What is the best explanation for this genetic situation?
A) Albino is recessive; black is dominant.
B) Albino is dominant; black is incompletely dominant.
C) Albino and black are codominant.
D) Albino is recessive; black is codominant.