This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacterial infections, Subject name: Dental
Which of the following is not approved for treatment of leprosy? 
Select and explain. 
A. Ofloxacin, B. Minocycline, C. Azathioprine, D. Rifampicin
C: Azathioprine
Answer: C: Azathioprine 
Explanation: Rifampicin is combined with dapsone to treat paucibacillary leprosy. Rifampicin and clofazimine are combined with dapsone to treat multibacillary leprosy. A single dose of combination therapy has been used to cure single lesion paucibacillary leprosy: rifampicin (600 mg), ofloxacin (400 mg), and minocycline (100 mg). Azathioprine is an immunosuppressive medication. It is used in rheumatoid ahritis, granulomatosis with polyangiitis, Crohn's disease, ulcerative colitis, and in kidney transplants to prevent rejection. Ref Harrison 20th edition pg 1212