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: Physiology
[{'content': 'Which of the following hormonal activity is expected immediately prior to Ovulation? \nSelect and explain. \nA. LH surge, B. FSH surge, C. Progestrone surge, D. Estrogen surge', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ovulation occurs due to the effect of increased concentration of LH. In the pre-ovulatory phase of the menstrual cycle, the ovarian follicle will undergo a series of transformations called cumulus expansion, which is stimulated by FSH. This is followed by LH surge.', 'role': 'assistant'}]