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': 'All of the following cephalosporins have good activity against Pseudomonas aeruginosa EXCEPT : \nSelect and explain. \nA. Cefadroxil, B. Cefepime, C. Cefoperazone, D. Ceftazidime', 'role': 'user'}, {'content': 'Answer: A \nExplanation: First generation cephalosporins like cefadroxil are mainly effective against gram +ve organisms and possess little activity against Pseudomonas.', 'role': 'assistant'}]