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
Pseudomonas is resistant to - 
Select and explain. 
A. Vancomycin, B. Aztreonam, C. Ciprofloxacin, D. Polymyxin B
A: Vancomycin
Answer: A: Vancomycin 
Explanation: Ans. is 'a' i.e., Vancomycin o Vancomycin is NOT active against pseudomonas.