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': 'Mestranol acts as a contraceptive by : \nSelect and explain. \nA. Inhibiting FSH secretion, B. Inhibiting LH secretion, C. Inhibiting tubal motility, D. Inhibiting nidation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Inhibiting FSH secretion', 'role': 'assistant'}]