This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Gynaecology & Obstetrics
[{'content': 'Minimum dose of estrogen in combined OCP&;s \nSelect and explain. \nA. 20mcg, B. 30cg, C. 35mcg, D. 50mcg', 'role': 'user'}, {'content': 'Answer: A \nExplanation: .', 'role': 'assistant'}]