Kathleen and Alphonse Are Expecting Their First Child, and Are

Kathleen and Alphonse are expecting their first child, and are having a pleasant conversation about the sex of the baby. Kathleen says, "Well, as long as all of the chromosomes are X, we'll be having a girl!" Which of the following would be the best answer for Alphonse to give?

A) "That isn't exactly right, since it is an XY chromosomal pattern that produces a female baby."
B) "Actually, it is only one pair of chromosomes that determines the sex of the baby."
C) "It is not the chromosomes, but the genes that make up the chromosomes that determine whether we'll have a son or a daughter."
D) "Since we are only in the second month of the pregnancy, we still have six months to go before the sex of the baby will be determined by the 15th and 16th pairs of chromosomes."