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 male patient presented with agitation, restlessness and neck stiffness. He had undergone treatment for penile ulcer - 3 years back. Lab investigation used for prognosis of treatment: \nSelect and explain. \nA. TPI, B. VDRL, C. FTA-ABS, D. Dark field microscopy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans (b) VDRL', 'role': 'assistant'}]