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: Unknown
[{'content': 'Oral combined contraceptive pills contain which one of the following sets of hormones? \nSelect and explain. \nA. Ethinyl estradiol, progestogen, and estrone, B. Progestogen and ethinyl estradiol, C. Progestogen and estrone, D. Estrone and ethinyl estradiol', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]