Human genetics question- biology?

Yes! the answer is A) 50%. Why because, 50% of sperms will contain X chromosome and 50% will contain Y chromosome. As it is a X linked character, and the chance of fusion between a sperm carrying X chromosome and an ovum is 50%. The probability of getting a son with soft tooth enamel is certainly will be 50% as the character is dominant, the character will be expressed.