This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
[{'content': 'Discoloration of the skin, mucosa and nails is sideeffect of \nSelect and explain. \nA. Zidovudine, B. Lamivudine, C. Stavudine, D. Enfuviide', 'role': 'user'}, {'content': 'Answer: A \nExplanation: .When nail discoloration is due to zidovudine, patients are usually able to repo if the discoloration preceded or coincided with the initiation of therapy. Another unusual side effect of zidovudine noted by some is a grayish-black discoloration of the tongue. Azidothymidine-induced nail pigmentation Ref Robbins 9/e pg 789', 'role': 'assistant'}]