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
Mechanism of action of quinolones is by? 
Select and explain. 
A. Inhibiting DHFRase, B. Inhibiting DNA gyrase, C. Inhibiting protein synthesis, D. Inhibiting cell wall synthesis
B: Inhibiting DNA gyrase
Answer: B: Inhibiting DNA gyrase 
Explanation: None