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: Dental
[{'content': '"Snail track ulcers" are seen in \nSelect and explain. \nA. Primary syphilis, B. Secondary syphilis, C. Tertiary syphilis, D. Latent syphilis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]