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
Tobacco usage has been associated with 
Select and explain. 
A. Hyperkeratosis, B. Erythema, C. Ulceration, D. None of the above
A: Hyperkeratosis
Answer: A: Hyperkeratosis 
Explanation: None