21. In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. Theheterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black femaleand an orange male?
(A) Tortoiseshell females; tortoiseshell males
(B) Black females; orange males
(C) Orange females; orange males
(D) Tortoiseshell females; black males