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': 'Single layer of varnish covers: \nSelect and explain. \nA. 55% of surface area, B. 25% of surface area, C. 35% of surface area, D. 80% of surface area', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Single layer of varnish cover -\xa055% of surface area.\n2-3 layers applied ⇒ 60 – 80%\xa0surface area covered.', 'role': 'assistant'}]