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: Medicine
[{'content': "All of the following are known predisposing factors for Alzheimer's disease except - \nSelect and explain. \nA. Down-syndrome, B. Low education level, C. Smoking, D. Female sex", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]