Answer:
100%
Step-by-step explanation:
The gene for color blindness is carried on the X chromosome. A woman who expresses the trait for color blindness has two copies of the allele for color blindness, one on each X chromosome. Since it is not carried on the Y chromosome, and boys always inherit their X chromosomes from their mothers, a son can only inherit a X chromosome with the allele for color blindness, meaning any son from this woman will be color blind.