This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Orthopaedics
[{'content': 'Which is NOT a malignant tumour? \nSelect and explain. \nA. Osteochondroma, B. Ewings sarcoma, C. Chondrosarcoma, D. Osteosarcoma', 'role': 'user'}, {'content': "Answer: A \nExplanation: (A) Osteochondroma ]A CLASSIFICATION OF BONE TUMOURS. MODIFIED AFTER REVISED WHO CLASSIFICATION - SCHAJOWICZ (1994)Predominant tissueBenignMalignant* Bone formingOsteomaOsteosarcoma:* central* peripheral* parosteal Osteoid osteomaOsteoblastoma* Cartilage formingChondromaChondrosarcoma: OsteochondromaChondroblastoma* central* peripheral* juxtacortical Chondromyxoid fibroma* clear-cell* mesenchymal* Fibrous tissueFibromaFibrosarcoma Fibromatosis * MixedChondromyxoid fibroma * Giant-cell tumoursBenign osteoclastomaMalignant osteoclastoma* Marrow tumours Ewing's tumour Myeloma* Vascular tissueHaemangiomaAngiosarcoma HaemangiopericytomaHaemangioendotheliomaMalignant haemangiopericytoma* Other connective tissueFibromaFibrosarcomaFibrous histiocytomaMalignant fibrous histiocytomaLipomaLiposarcoma* Other tumoursNeurofibromaAdamantinoma NeurilemmomaChordoma", 'role': 'assistant'}]