56. In bird, the sex chromosome presented in egg, rather than sperm, determines the gender of the offspring. Therefore, females are ZW while males are ZZ. Which of the following statements is correct? (A) W linked recessive mutation will never cause disease in males. (B) Z linked recessive mutation will only affect female offspring. (C) Unfertilized egg cells only carry Z chromosome. (D) Some sperm cells carry W chromosome. (E) None of the above.