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: Anatomy
[{'content': 'How many lactiferous ducts open in nipple ? \nSelect and explain. \nA. 0 -10, B. 15 -20, C. 25 -50, D. 50 -75', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The nipple is pierced by 15-20 lectiferous ducts.', 'role': 'assistant'}]