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': "The specific test for Treponema pallidum is \nSelect and explain. \nA. VDRL, B. Kahn's test, C. TPHA, D. Widal test", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]