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': "Codman's triangle is seen in – \nSelect and explain. \nA. Chondroblastoma, B. Osteosarcoma, C. Chandrosarcoma, D. GCT", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]