Hemophilia Is Caused by an X-Linked Recessive Mutation in Humans

Multiple Choice

Hemophilia is caused by an X-linked recessive mutation in humans.If a woman whose paternal uncle (father's brother) was a hemophiliac marries a man whose brother is also a hemophiliac, what is the probability of their first child having hemophilia (Note: assume that there are no other cases of hemophilia in the pedigree and no hidden carriers) ?

A) 0
B) 1/4
C) 1/2
D) 1/8
E) 1