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
[{'content': 'Dofetilide belong to? \nSelect and explain. \nA. Class I antiarrythmic, B. Class II antiarrythmic, C. Class III antiarrythmic, D. Class IV antiarrythmic', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ibutilide, dofetilide, sotalol, amiodarone are class 3 agents they are potassium channel blockers- they r broad spectrum antiarrhythmic agents they increase QT interval', 'role': 'assistant'}]