This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti Microbial, Subject name: Pharmacology
Drug given for antibiotic associated pseudomembranous enterocolitis and is part of anti H. Pylori treatment: 
Select and explain. 
A. Amoxicillin, B. Vancomycin, C. Metronidazole, D. Clotrimazole
C: Metronidazole
Answer: C: Metronidazole 
Explanation: Ans. C. MetronidazoleTriple drug regimen given for H. Pylori include- clarithromycin, amoxicillin, tetracycline, metronidazole. Out of all these drugs metronidazole is drug of choice for pseudomembranous colitis.