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
[{'content': 'Multiple myeloma has been seen commonly after exposure to \nSelect and explain. \nA. Radioactive isotopes, B. Gold, C. Asbestos, D. Organic dyes', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]