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': 'One of the following is a treponemal test for diagnosis of syphilis \nSelect and explain. \nA. FTAB, B. Widal test, C. Wasserman test, D. Kahn test', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]