This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': 'Drug not used for Pseudomembranous colitis \nSelect and explain. \nA. Metronidazole, B. Vancomycin, C. Fidaxomycin, D. Streptogramins', 'role': 'user'}, {'content': 'Answer: D \nExplanation: All except streptogramins are used. Drug of choice for pseudomembranous colitis is metronidazole,in resistant cases vancomycin given orally. Fidaxomycin is newer class of macrolide type of antibiotic used specially for PMC Ref:KDT 6/e p799', 'role': 'assistant'}]