Ovulation in a women with 28 day cycle occurs at-

Ans. is 'a' i.e., 14 days prior to mensturation o The length of the secretory' phase is remarkably constant at about 14 d, and the variations seen in the length of the menstrual cycle are due for the most part to variations in the length of the proliferative phase. Thus ovulation occurs 14 days before the start of next menstruation.