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': 'Diagnosis of Dengue fever can be made earliest by? \nSelect and explain. \nA. Viral culture, B. NS - 1 antigen detection, C. lgG antibody detection, D. Nucleic acid test', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., NS-1 antigen detection", 'role': 'assistant'}]