To solve this problem, we need to determine the genetic inheritance of color blindness in the children of the couple described.$\newline \bullet$Color blindness is a sex-linked recessive trait, located on the X chromosome.$\newline \bullet$Let's denote the alleles as follows:$\newline - X^{C}$ for the normal vision allele$\newline - X^{c}$ for the color-blind allele$\newline$ - Y for the male chromosome$\newline$The man's genotype:$\newline \bullet$Since his father was color blind, the man must have inherited a normal X chromosome from his mother $(X^{C}Y). \newline$The woman's genotype:$\newline \bullet$Her mother was color blind $(X^{c}X^{c})$ and her father was normal $(X^{C}Y)$, so she must be a carrier $(X^{C}X^{c}).\newline$Now, let's determine the possible genotypes of their children:$\newline \bullet$For male children, the possible combinations are:$\newline$ - $X^{C}$ from the mother and Y from the father $(X^{C}Y)$ - normal vision$\newline$ - $X^{c}$ from the mother and Y from the father $(X^{c}Y)$ - color blind$\newline$Since the mother is a carrier, there is a 50% chance of passing the $X^{c}$ allele to her sons.$\newline$Therefore, 50% of their male children will be color blind.$\newline$This corresponds to Option 3.