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
Which of the following doesn't have any effect on pseudomonas? 
Select and explain. 
A. Ticaracillin, B. Carbenicillin, C. Azlocillin, D. Naficillin
D: Naficillin
Answer: D: Naficillin 
Explanation: Nafcillin is a narrow-spectrum bactericidal antibiotic agent of the penicillin class. It is useful for susceptible infections due to penicillinase-producing staphylococci. Piperacillin and Mezlocillin also acts on pseudomonas.