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': 'Duraphat is: \nSelect and explain. \nA. Lacquer, B. Sodium Fluoride in varnish form, C. Stannous Fluoride, D. Sodium Fluoride 2%', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]