Genes for the M and L Pigments Are on the X

Multiple Choice

Genes for the M and L pigments are on the X chromosome, and males have only one X chromosome, while women have two. This explains why

A) men are more likely than women to have visual impairments.
B) women are more likely than men to have visual impairments.
C) women and men are about equally likely to have visual impairments.
D) the incidence of visual impairments is most affected by age.