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
Which one of the following is not an antiretroviral drug : 
Select and explain. 
A. Saquinavir, B. Ganciclovir, C. Indinavir, D. Atazanavir
B: Ganciclovir
Answer: B: Ganciclovir 
Explanation: None