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
All of the following carcinogens play a role in carcinoma of lungs except: 
Select and explain. 
A. Beryllium, B. Nickel, C. Cadmium, D. Arsenic
C: Cadmium
Answer: C: Cadmium 
Explanation: None