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: Social & Preventive Medicine
[{'content': 'What is the content of ethinyl estradiol in very low \nSelect and explain. \nA. 30µg, B. 25µg, C. 20µg, D. 15µg', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]