This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti-Arrhythmic, Subject name: Pharmacology
Drug of choice of paroxysmal supraventricular tachycardia is - 
Select and explain. 
A. Adenosine, B. Digitalis, C. Procainamide, D. Mexiletine
A: Adenosine
Answer: A: Adenosine 
Explanation: Ans. is 'a'i.e., Adenosine Drugs of PSVT-1st choice - Adenosine2nd choice - CCBs (verapamil, diltiazem) or b-blockers.