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': 'Pit and fissure sealant used in primary prevention of caries is \nSelect and explain. \nA. BIS - GMA, B. Duraphat, C. Fluor protector, D. APF gel', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]