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': "The % formaldehyde in buckely's formocresol is \nSelect and explain. \nA. 15%, B. 19%, C. 25%, D. 20%", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]