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: Skin
[{'content': 'Diagnostic test for syphilis: March 2013 \nSelect and explain. \nA. VDRL, B. RPR, C. FTA-ABS, D. IgG ELISA', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C i.e. FTA-ABS', 'role': 'assistant'}]