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: Pediatrics
[{'content': "Ewing's tumour arises from – \nSelect and explain. \nA. Mesothelial cell, B. Endothelial cell, C. Squamous cell, D. None of the above", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]