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: Pharmacology
[{'content': 'All of the following are topically used sulphonamides except - \nSelect and explain. \nA. Sulphacetamide, B. Sulphadiazine, C. Silver sulphadiazine, D. Mafenide', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans is 'b' i.e., Sulphadiazine Topical Sulfonamides - Sulfacetamide sodium, Mafenide, silver sulfadiazine.", 'role': 'assistant'}]