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
[{'content': 'Resistance to zidovirdine 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 triphosphate formation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: "Resistance to AZT (Zidovudine) occurs by point mutations which alter the reverse transcriptase enzyme,"', 'role': 'assistant'}]