This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'How many hours prior to ovulation does LH Surge occur? \nSelect and explain. \nA. 6-8 hrs, B. 10-16 hrs, C. 18-24 hrs, D. More than 24 hrs', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans:C.)18-24 hours. Sustained peak level of estrogen for 24-36 hours in the late follicular phase - LH surge occurs from the anterior pituitary. Ovulation approximately occurs 16-24 hours after the LH surge. LH peak persists for about 24 hours. The LH surge stimulates completion of reduction division of the oocyte and initiates luteinization of the granulosa cells, synthesis of progesterone and prostaglandins. Ref: Dutta', 'role': 'assistant'}]