This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mycobacterial Infections, Subject name: Dental
The most potent anti-leprotic drug is? 
Select and explain. 
A. Rifampicin, B. Dapsone, C. Clofazimine, D. Sulfasalazine
A: Rifampicin
Answer: A: Rifampicin 
Explanation: Rifampicin is bactericidal for M. leprae in very low dosage and acts much more rapidly than Dapsone, rendering the patient non-contagious in a few days or weeks. It acts by inhibiting DNA dependent RNA polymerase.