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': 'Principle of pole dilatation is: \nSelect and explain. \nA. Dilatation of alveolus., B. Expansion of bony socket., C. Both of the above., D. None.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]