Ahusband and wife have normal vision, although both of the couple's fathers are red–green color-blind, an inherited x-linked recessive condition.

a. what is the probability that the couple's first child will be a normal son? enter your answer as a fraction
b. what is the probability that the couple's first child will be a normal daughter? enter your answer as a fraction
c. what is the probability that the couple's first child will be a color-blind son? enter your answer as a fraction
d. what is the probability that the couple's first child will be a color-blind daughter? enter your answer as a fraction