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: Psychiatry
Following are predispositions to 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: Risk factors for Alzheimer's disease:- Old age, female sex, positive family history, head trauma, low educational status, depression, metabolic (diabetes, hypercholesterolemia, elevated homocysteine), hypertension, CVA (stroke), Heavy metals (mercury, aluminium), genetic factors, down's syndrome.