Genotype QUESTION PLEASE HELP ME?

This is because the allele is carried on the X chromosome. A father gives a Y chromosome to his son, the affected male, so he cannot give the m allele. The mother, on the other hand gives an X chromosome to all her children, so she is capable of ping the allele on to sons or daughters. (If it makes it any clearer, a father can (and will) p on the m allele to any of his daughters.)