If a colour-blind man marries a woman who is homozygous for normal vision, the probability of their son being colour blind is
0
0.5
0.75
1
The genotype of colour blind man =
The genotype of normal female =
Thus, the cross between these two individuals will give the possible combinations and from Punnett Square, it is evident that none of the sons is victims of the disease. So none of them will be colour blind.