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 zidovudine develops due to- \nSelect and explain. \nA. Mutations 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: Ans. is \'a\' i.e., Mutations at reverse transcriptase "Resistance to Zidovudine occurs by point mutation which alters reverse transcriptase enzyme. In the past when AZT was used alone, > 50% patients became nonresponsive to AZT within 1-2 years therapy due to growth of resistant mutants" - KDT', 'role': 'assistant'}]