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': 'Oral vancomycin can be used for treatment of : \nSelect and explain. \nA. Hepatic encephalopathy, B. Pseudomembranous colitis, C. Staphylococcal food poisoning, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]