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': 'Which of the following anti-HIV drug should never be given as re–challenge once history of producing allergic reaction with drug is known ? \nSelect and explain. \nA. Lamivudine, B. Abacavir, C. Zidovudine, D. Nelfinavir', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]