This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Osteogenic Sarcoma, Subject name: Orthopaedics
[{'content': "Radiological inv. shows sun ray appearance; dx is: \nSelect and explain. \nA. Osteosarcoma, B. GCT, C. Osteomyelitis, D. Ewing's sarcoma", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' ie Osteosarcoma Classical radiological features*Sun ray appearance*-OsteosarcomaOnion peel appearance*-EwingSoap bubble appearance*-OsteoclastomaPatchy calcification*-ChondrosarcomaWormian bones*-Osteogenesis imperfectaTrethowan's sign*-Stipped capital femoral epiphysisAneurysmal sign*-TB spine.", 'role': 'assistant'}]