This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti Microbial, Subject name: Pharmacology
[{'content': 'Mechanism of action of quinolones is? \nSelect and explain. \nA. DNA gyrase inhibitors, B. Bind to 30 s unit, C. Bind to bacterial cell membrane, D. Bind to tetrahydofolate reductase', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ANSWER: (A) DNA gyrase inhibitorsREF: Goodman G ill man s 11th ed p. 722The quinolone antibiotics target bacterial DNA gyrase and topoisomerase IV. For many gram positive bacteria, topoisomerase IV is the primary target. For many gram-negative bacteria, DNA gyrase is the primary quinolone target.', 'role': 'assistant'}]