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': 'Anti progesterone drug is : \nSelect and explain. \nA. Cyproterone, B. Mifepristone, C. Spironolactone, D. Tamoxifen', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Mifepristone', 'role': 'assistant'}]