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': 'Surgical wound of trans-alveolar extraction mostly falls under which of these categories? \nSelect and explain. \nA. Clean, B. Clean-contaminated, C. Dirty-infected, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Most of these procedures fall under clean-contaminated or contaminated categories.', 'role': 'assistant'}]