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': 'The best predictor of ovulation is : \nSelect and explain. \nA. Estrogen peak, B. Follicle stimulating hormone (FSH) surge, C. Onset of the LH surge, D. Preovulatory rise in progesterone', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Onset of the LH surge', 'role': 'assistant'}]