A couple is planning the conception of their first child.

(A) Ovulation is dependent on average length of menstrual cycle, not standard 14 days. (B) Ovulation occurs 14+2 days before next menses (34 minus 14 does not equal 16). (C) Ovulation occurs 14+2 days before next menses (34 minus 14 equals 20). (D) Ovulation occurs 14+2 days before next menses (34 minus 14 does not equal 22).