This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
Which of the following drugs can cause torsades'de pointers? 
Select and explain. 
A. Quinidine, B. Lignocaine, C. Esmolol, D. Flecainide
A: Quinidine
Answer: A: Quinidine 
Explanation: class 1A agents, class 3 antiarrythymic agents commonly produce torsades de pointes class 1 a- quinidine, disopyramide, procainamide class 1b agents doesnt produce torsades pointes-eg lidocaine, phenytoin, mexiletine, tocainide flecainide is class 1c REF.Essentials of Pharmacology KD Tripathi 8th ed.