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': "Dakin's solution is \nSelect and explain. \nA. 0.5% NaOCl, B. 2.5% NaOCl, C. 1.25% NaOCl, D. 5.2% NaOCl", 'role': 'user'}, {'content': 'Answer: A \nExplanation: NaOCl as a buffered 0.5% solution was recommended for irrigation of wound during world war I by Dakin. Coolidge introduced NaoCl to\xa0endodontics.', 'role': 'assistant'}]