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': "Laryngeal oedema - a life-threatening situation is seen\nin association with: \nSelect and explain. \nA. Cavernous sinus thrombosis, B. Infection of pharyngeal tonsils, C. Ludwig's angina, D. Cellulitis", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]