This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tonsils, Subject name: ENT
[{'content': "All of the following cause a grey white membrane on the tonsil, except: \nSelect and explain. \nA. Infectious mononucleosis, B. Ludwig's angina, C. Streptococcal tonsillitis, D. Diphtheria", 'role': 'user'}, {'content': "Answer: B \nExplanation: (b) Ludwig's angina(Ref. Scott Brown, 8th ed., Vol 3; 550)Ludwig's angina is cellulitis of the sub-mandibular space.The rest of the options can cause membrane over tonsils.", 'role': 'assistant'}]