This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and breast, Subject name: Surgery
[{'content': 'Serous or serosanguinous nipple discharge may be suggestive of all of the following except \nSelect and explain. \nA. Mastitis, B. Carcinoma, C. Duct ectasia, D. Intraductal papilloma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Mastitis usually associated with purulent nipple discharge', 'role': 'assistant'}]