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: Social & Preventive Medicine
[{'content': 'A research team conducted a nation wide survey of Industries and factories. While arranging the data they observed that the most common occupational cancer was \nSelect and explain. \nA. CA skin, B. CA bladder, C. CA lung, D. Leukemia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]