This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bone Tumour, Subject name: Orthopaedics
[{'content': "Epiphyseal origin tumour is \nSelect and explain. \nA. Osteo claustoma, B. Osteogenic sarcoma, C. Ewing's sarcoma, D. Osteo blastoma", 'role': 'user'}, {'content': "Answer: A \nExplanation: (Osteoclaustoma) (181 - Apley's 8th)* Ewing's sarcoma - is believed to arise from endothelial cells / Diaphysis* Osteogenic sarcoma - Metaphysis* Chondrosarcoma - Any where in the bone* Osteoclaustoma & Chondroblastoma - Epiphysis* Osteoblastoma - diaphysis or metaphysis* Giant cell tumour (oslcoclaustoma) is a lesion of uncertain origin* that appears in mature bone", 'role': 'assistant'}]