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': 'Most important principle during extraction: \nSelect and explain. \nA. Least trauma to bone while extracting whole tooth out, B. Least trauma to mucosa while extracting the whole tooth out, C. Least trauma to both bone and mucosa while extracting the tooth in pieces, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]