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: Orthopaedics
[{'content': "Increased Radio - isotope uptake is seen in \nSelect and explain. \nA. Osteoclastoma, B. Enchondroma, C. Pseudoarthrosis, D. Ewing's sarcoma", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]