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': 'The principal problem with tuberosity reduction is: \nSelect and explain. \nA. Poor access, B. Formation of oro-antral fistula, C. Infection, D. Damage to posterior superior alveolar nerve', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]