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': "Which of the following conditions may necessitate\nemergency tracheostomy to prevent suffocation \nSelect and explain. \nA. Cellulitis, B. Ludwig's angina, C. Cavernous sinus thrombosis, D. Maxillary sinusitis", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]