Please help me with these biology questions?

A son who is not colorblind inherited a dominant allele for the trait from his mother. Since a colorblind mother is double-recessive, she cannot give a dominant allele to her son. The father must give a Y chromosome to his son, so he cannot give an allele for colorblindness at all. Therefore, any sons the couple produces must be colorblind. The answer is A) 0%