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: Microbiology
[{'content': 'Most sensitive test for HIV \nSelect and explain. \nA. ELISA, B. western blot, C. Lymph node biopsy, D. Southern blot', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Most sensitive test for HIV is ELISA.', 'role': 'assistant'}]