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
Patch on tonsil is not caused by: 
Select and explain. 
A. Vincent's angina, B. Candida, C. Staphylococcus, D. Ludwig's angina
D: Ludwig's angina
Answer: D: Ludwig's angina 
Explanation: (d) Ludwig's angina(Ref. Scott Brown, 8th ed., Vol 3; 550)Ludwig's angina does not involve tonsil. The other options can lead to patch/pseudomembrane on the tonsil.