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': 'Fluoroquinolones act on - \nSelect and explain. \nA. DNA histone proteins, B. DNA gyrase, C. Camp, D. mRNA polymerise', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., DNA gyrase o Fluoroquinolones (including ciprofloxacin) inhibit DNA gyrase and topoisomerase IV. For gram negative bacteria, the primary target is DNA gyrase, while topoisomerase IV is inhibited in gram positive bacteria.", 'role': 'assistant'}]