70. Short hair (L) is dominant to long hair (l). If a short-haired animal of unknown origin is crossed with a long-haired animaland they produce one long-haired and one short-haired offspring, this would indicate that
(A) the short-haired animal was pure-breeding.
(B) the short-haired animal was not pure-breeding.
(C) the long-haired animal was not pure-breeding.
(D) the long-haired animal was pure-breeding.
(E) none of these can be determined with two offspring.