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': "Which of the following doesn't have any effect on pseudomonas? \nSelect and explain. \nA. Ticaracillin, B. Carbenicillin, C. Azlocillin, D. Naficillin", 'role': 'user'}, {'content': 'Answer: D \nExplanation: 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.', 'role': 'assistant'}]