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
[{'content': 'Qt. prolonged is associated with - \nSelect and explain. \nA. Hypercalcemia, B. Type la anti arrythmic drugs, C. Torsade de pointes, D. Atrial fibrillation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ref Harrison 20th edition pg 1423', 'role': 'assistant'}]