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': 'In the year 1971 first Pit and Fissure sealant was developed \nSelect and explain. \nA. NUVA SEAL., B. NEW SEAL., C. SEALAPEX., D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]