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: Unknown
Tumour arising from diaphysis - 
Select and explain. 
A. Osteogenic sarcoma, B. Ewing's sarcoma, C. Osteoclastoma, D. Osteochondroma
B: Ewing's sarcoma
Answer: B: Ewing's sarcoma 
Explanation: Ans-B