In Cats an X-Linked Pair of Alleles, B and B

Short Answer

In cats an X-linked pair of alleles, B and b , controls color of fur. The alleles are incompletely dominant: B produces black, b produces yellow, and Bb produces tortoise-shell.
(a) A yellow cat had a litter of two tortoiseshell kittens and one yellow. What is the sex of the yellow kitten?
(b) A tortoiseshell cat brings home a litter of black, yellow, and tortoiseshell kittens. The color of which sex would tell you the color of the tomcat that produced them?
(c) A yellow male is crossed with a tortoiseshell female. If the female has all male kittens in her litter of four, what color(s) would they be?
(d) A tortoiseshell cat brings home her litter of black, yellow, and tortoiseshell kittens. By what method could you possibly decide whether the male parent was the black tomcat next door?