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: Medicine
All are used in AIDS except - 
Select and explain. 
A. Zidovudine, B. Stavudine, C. Ribavarin, D. Lamivudine
C: Ribavarin
Answer: C: Ribavarin 
Explanation: None