This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Musculoskeletal Radiology, Subject name: Radiology
[{'content': "The X-ray of the right distal tibia and fibula is shown, which possibly represent : \nSelect and explain. \nA. Ewing's sarcoma, B. Osteosarcoma, C. Soft tissue tumor with fibular involvement, D. Osteoclastoma", 'role': 'user'}, {'content': "Answer: B \nExplanation: Lesion involving distal fibula with typical sun burst periosteal reaction and adjacent soft tissue swelling is noted, this is diagnostic of osteosarcoma. X-ray of osteosarcoma shows the following features : * An area of irregular destruction in the metaphysis, sometimes overshadowed by the new bone formation. * Periosteal reaction * Codman's triangle * Sun-ray appearance", 'role': 'assistant'}]