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
Class III Vaughan - Williams classification consists of? 
Select and explain. 
A. Na channel blocker, B. Beta blocker, C. K channel blocker, D. Calcium channel blocker
C: K channel blocker
Answer: C: K channel blocker 
Explanation: Ans. is 'c' i.e., K channel blocker