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: Pathology
Smoking is not a risk factor for 
Select and explain. 
A. Lung carcinoma, B. Osteoporosis, C. Nonunion of bones, D. Alzhiemers disease
D: Alzhiemers disease
Answer: D: Alzhiemers disease 
Explanation: Answer- D. Alzhiemers disease"Recent research has shown that smoking is a signifcant risk factor for vascular dementia and Alzheimer's disease, with smokers twice as likely to develop the disease as non-smokers".