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
Oral vancomycin can be used for treatment of ? 
Select and explain. 
A. Hepatic encephalopathy, B. Pseudomembranous colitis, C. Staphylococcal food poisoning, D. None of the above
B: Pseudomembranous colitis
Answer: B: Pseudomembranous colitis 
Explanation: Ans. is 'b' i.e., Pseudomembranous colitis o Vancomycin is used orally to treat pseudomembranous colitis by clostridium difficile because it is not absorbed from the gastrointestinal tract and higher concentration reaches the colon.