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
All of the following are known predisposing factors for Alzheimer's disease except : 
Select and explain. 
A. Down-syndrome, B. Low education level, C. Smoking, D. Female sex
C: Smoking
Answer: C: Smoking 
Explanation: Answer is C (Smoking):Smoking has not been mentioned as a risk factor, for Alzheimer's disease.