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: Medicine
Which of the following drugs act against Pseudomonas? 
Select and explain. 
A. Nafcillin, B. Cloxacillin, C. Methicillin, D. Piperacillin
D: Piperacillin
Answer: D: Piperacillin 
Explanation: None