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
The most important factor associated with causation of head and neck carcinoma is 
Select and explain. 
A. Intravenous drug abuse, B. Exposure to nickel, C. History of syphilis, D. Tobacco use
D: Tobacco use
Answer: D: Tobacco use 
Explanation: None