This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Normal Menstruation, Abnormal Menstruation, Menopausal Physiology and forsight of conception, Subject name: Gynaecology & Obstetrics
[{'content': 'Onset of LH surge precedes ovulation by: \nSelect and explain. \nA. 12 hours, B. 24 hours, C. 36 hours, D. 48 hours', 'role': 'user'}, {'content': 'Answer: C \nExplanation: LH surge 36 hrs (24- 36 hrs) before ovulation. LH peak 12 hrs before ovulation.', 'role': 'assistant'}]