<prompt> All of the following cause a grey white membrane on the tonsil, except:Infectious mononucleosisLudwigs anginaStreptococcal tonsillitisDiphtheria  <response>: b Ludwigs anginaRef. Scott Brown, 8th ed., Vol 3; 550Ludwigs angina is cellulitis of the sub-mandibular space.The rest of the options can cause membrane over tonsils. 