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: Surgery
[{'content': 'Split skin grafts in young children should be harvested from - \nSelect and explain. \nA. Buttocks, B. Thigh, C. Trunk, D. Upper limb', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]