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': 'Bone scan in multiple myeloma shows – \nSelect and explain. \nA. Hot spot, B. Cold spot, C. Diffusely increased uptake, D. Diffusely decreased uptake', 'role': 'user'}, {'content': 'Answer: B \nExplanation: There is no compensatory osteoblastic activity in multiple myeloma, therefore lesions appear as cold spot on bone scan.', 'role': 'assistant'}]