Two Forms of Hemophilia Are Determined by Genes on the X

Multiple Choice

Two forms of hemophilia are determined by genes on the X chromosome in humans.Assume that a phenotypically normal woman whose father had hemophilia is married to a normal man.What is the probability that their first son will have hemophilia?

A) zero
B) 1/2
C) 100%
D) 1/4
E) 1/3