This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Organic Mental Disorders, Subject name: Psychiatry
[{'content': "Following are predispositions of Alzheimer's disease except: \nSelect and explain. \nA. Down's syndrome, B. Head trauma, C. Smoking, D. Low education group", 'role': 'user'}, {'content': "Answer: C \nExplanation: Smoking is considered to be one of the protective factors in Alzheimer's disease; however this finding has been inconsistent across the studies. Risk factor for Alzheimer disease Age Head injury HTN Insulin resistance Depression Down syndrome", 'role': 'assistant'}]