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: Anatomy
[{'content': 'Most common site of Ewings sarcoma \nSelect and explain. \nA. Upper end of tibia, B. Shaft of tibia, C. Lower end of femur, D. Shaft of femur', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Most common site of Ewings sarcoma is diaphysis of femur followed by diaphysis of tibia Refer : Textbook of skeletal oncology p 315', 'role': 'assistant'}]