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': 'Osteoblastic metastasis is seen – \nSelect and explain. \nA. Prostate carcinoma, B. Multiple myeloma, C. Thyroid carcinoma, D. Renal carcinoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]