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
[{'content': 'Resistance to zidovudne develops due to: \nSelect and explain. \nA. Mutation at reverse transcriptase, B. Increased efflux of the drug from inside the cell, C. Increased metabolism of the drug, D. Decreased zidovudine 5 triphosphate formation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Zidovudine;It is a thymidine analogue (azidothymidine, AZT), the prototype NI. After phosphorylation in the host cell-zidovudine triphosphate selectively inhibits viral reverse transcriptase (RNA-dependent DNA polymerase) in preference to cellular DNA polymerase Resistance to AZT occurs by point mutations which alter reverse transcriptase enzyme. ESSENTIALS OF MEDICAL PHARMACOLOGY K.D.TRIPATHI SIXTH EDITION PAGE NO:770', 'role': 'assistant'}]