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: Pharmacology
[{'content': 'Class III Vaughan - Williams classification consists of? \nSelect and explain. \nA. Na channel blocker, B. Beta blocker, C. K channel blocker, D. Calcium channel blocker', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., K channel blocker", 'role': 'assistant'}]