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': "On 3 phase 99m Tc - MDP bone scan, which of the following bone lesions will show least osteoblastic activity - \nSelect and explain. \nA. Paget' disease, B. Osteoid osteoma, C. Fibrous dysplasia, D. Fibrous cortical defect", 'role': 'user'}, {'content': "Answer: D \nExplanation: Osteoid osteoma, Paget's disease and fibrous dysplasia have osteoblastic activity, therefore, show increased radioisotope uptake on bone scan.\nFibrous cortical defect shows no radioisotope uptake as it has no osteoblastic activity.", 'role': 'assistant'}]