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
Increased incidence of squamous cell carcinoma of the skin is due to all except: 
Select and explain. 
A. Ultraviolet radiation, B. Actinic keratitis, C. Alcohol, D. None of the above
D: None of the above
Answer: D: None of the above 
Explanation: None