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
[{'content': 'All are used for AIDS except- \nSelect and explain. \nA. Fanciclovir, B. Ritonavir, C. Stavudine, D. Indinavir', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]