Refer to the Following Information to Answer the Questions Below

Multiple Choice

Refer to the following information to answer the questions below.
A man who is an achondroplastic dwarf with normal vision marries a colour-blind woman of normal height. The man's father was 6 feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green colour blindness is X-linked recessive.
-What proportion of their sons would be colour-blind and of normal height?

A) none
B) half
C) one out of four
D) three out of four
E) all