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
Drug of choice for torsades de pointes? 
Select and explain. 
A. Terfenadine, B. Quinidine, C. Isoprenaline, D. Magnesium sulphate
D: Magnesium sulphate
Answer: D: Magnesium sulphate 
Explanation: Mg sulfate is used for prolonged QT syndrome or Torsades de pointes. Quinidine and terfenadine cause Torsades de pointesRef: Goodman Gillman 11th ed pg 929-930