This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Pharmacology
[{'content': 'Lignocaine is useful: \nSelect and explain. \nA. Atrial fibrillation, B. PSVT, C. Digitalis induced toxicity, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C. Digitalis induced toxicityDOC for atrial fibrillation- verapamil. PSVT- adenosine, Digitalis induced toxicity- lignocaine.', 'role': 'assistant'}]