In Humans, Normal Vision Dominates Color-Deficiency, and Both Are X-Linked

Multiple Choice

In humans, normal vision dominates color-deficiency, and both are X-linked. (The genes are located on the X chromosome.) A color-deficient male marries a woman who is heterozygous for normal vision. If they have a boy, the chance that he will be color-deficient is

A) 100%.
B) 0%.
C) 75%.
D) 50%.