This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sex Hormones, Subject name: Physiology
Ovulation in a women with 28 day cycle occurs at- 
Select and explain. 
A. 14 days prior to mensturation, B. Just before LH surge, C. Just after corpus leuteal maturation, D. Due to progesterone rise
A: 14 days prior to mensturation
Answer: A: 14 days prior to mensturation 
Explanation: 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.