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: Radiology
[{'content': 'Radioactive phosphorus is used in the treatment of – \nSelect and explain. \nA. Polycythemia, B. Thyroid metastasis, C. Multiple myeloma, D. Embrynal cell carcinoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Amongst the given options, Radioactive phosphorus has a well-established role in polycythemia vera. It has also been tried in multiple myeloma, however, its use for this is still debatable.', 'role': 'assistant'}]