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 antigen detection is ? \nSelect and explain. \nA. RIA, B. ELISA, C. Immunofluorescence, D. Passive hemagglutination', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., RIA", 'role': 'assistant'}]