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
Following are predispositions of Alzheimer's disease except: 
Select and explain. 
A. Down's syndrome, B. Head trauma, C. Smoking, D. Low education group
C: Smoking
Answer: C: Smoking 
Explanation: 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