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': 'Congenital syphilis can be best diagnosed by: \nSelect and explain. \nA. IgM FTAabs, B. IgG FTAabs, C. VDRL, D. TPI', 'role': 'user'}, {'content': 'Answer: A \nExplanation: IgM-FTA-Abs test is a modification to identify fetal IgM and clarify the diagnosis of congenital syphilis or a re-infection. Ref: Color Atlas of Dermatology By Main Rocken, Main Schaller - 2012', 'role': 'assistant'}]