This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematology and CVS, Subject name: Pharmacology
Which of the following antiarrhythmic drugs can decrease the slope of Phase 0 and prolong the action potential duration? 
Select and explain. 
A. Lignocaine, B. Propanolol, C. Quinidine, D. Adenosine
C: Quinidine
Answer: C: Quinidine 
Explanation: Na+ channel blockers reduce the slope of phase 0 whereas K+ channel blockers prolong the APD. Both of these propeies are present in class Ia antiarrhythmics like quinidine and procainamide.