This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy, Subject name: Pharmacology
Which of the following drug is a reverse transcriptase inhibitor? 
Select and explain. 
A. Indinavir, B. Ritonavir, C. Nelfinavir, D. Abacavir
D: Abacavir
Answer: D: Abacavir 
Explanation: ANTIVIRAL DRUG: CLASSI FICATION 1.Anti-Herpes virus Idoxuridine, Acyclovir, Valacyclovir, Famciclovir, Ganciclovir*, Foscarnet* 2 Anti-Retrovirus (a) Nucleoside reverse transcriptase inhibitors (Nis): Zidovudine (AZT), Didanosine, Zalcitabine*, Stavudine, Lamivudine, Abaca vir (b) Nonnucleoside reverse transcriptase inhibitors (NNis): Nevirapine, Eirenz, Delavirdine* (c) Protease inhibitors: Ritonavir, Indinavir, Nelfinavir, Saquinavir, Amprenavir*, Lopinavir 3. Anti-Influenza virus Amantadine, Rimantadine* 4. NonselectiVe antiviral drugs Ribavirin, Lamivudine, Adefovir dipivoxil, Interferon alpha. ESSENTIALS OF MEDICAL PHARMACOLOGY K.D.TRIPATHI SIXTH EDITION PAGE NO:767