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: Medicine
[{'content': 'Feature of Torsade de pointes is - \nSelect and explain. \nA. Wide QRS complex, B. Short QRS complex, C. Prolonged QTc interval, D. Short QTc interval', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]