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': 'A man with very high fever shows strongly positive agglutination test with OXK antigen. The most likely diagnosis is- \nSelect and explain. \nA. Tsutsugamushi fever, B. Trench fever, C. Undulent fever, D. Relapsing fever', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]