A man who is an achondroplastic dwarf with normal vision marries a color-blind woman of normal height. The man's father was of normal height, and both the woman's parents were also of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is an X-linked recessive trait. They have a daughter who is a dwarf with normal color vision. What is the probability that she is heterozygous for both genes?

100%
75%
50%
0%