A Man Who Is a Dwarf Due to Achondroplasia and Has

Multiple Choice

A man who is a dwarf due to achondroplasia and has normal vision marries a color-blind woman of normal height.The man's father was 6 feet tall,and both the woman's parents were of average height.Achondroplasia is autosomal dominant,and red-green color blindness is X-linked recessive.
What proportion of their sons would be color-blind and of normal height?

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