This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti-HIV Drugs, Subject name: Pharmacology
All of the following drugs are HIV protease inhibitors except? 
Select and explain. 
A. Indinavir, B. Abacavir, C. Atazanavir, D. Ritonavir
B: Abacavir
Answer: B: Abacavir 
Explanation: Drugs ending with 'NAVIR' are HIV protease inhibitors. Abacavir is a nucleoside reverse transcriptase inhibitor of HIV