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': 'Fastest acting drug in leprosy is - \nSelect and explain. \nA. Rifampicin, B. Dapsone, C. Clofazimine, D. Ethionamide', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. is `a\' i.e., Rifampicin "Rifampicin is the most active agent for leprosy".', 'role': 'assistant'}]