This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
Torsade-de- pointes is caused by- 
Select and explain. 
A. Hypermagnesemia, B. Metabolic acidosis, C. Hypomagnesemia, D. Metabolic alkalosis
C: Hypomagnesemia
Answer: C: Hypomagnesemia 
Explanation: Torsades-de-pointes is a form of VT seen as a complication of prolonged ventricular repolarisation. It is seeen in hypomagnesemia. It is not seen in hypermagnesemia,metabolic acidosis,metabolic alkalosis Ref Harrison 20th ed pg 1436