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': 'Extraction of following isolated residual maxillary tooth offers the hazard of fracture of tuberosity: \nSelect and explain. \nA. 3rd molar, B. 1st molar, C. 2nd molar, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Extraction of isolated residual maxillary molar offers the hazard of fracture of tuberosity or floor of the antrum.', 'role': 'assistant'}]