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
Dakin's solution is 
Select and explain. 
A. 0.5% NaOCl, B. 2.5% NaOCl, C. 1.25% NaOCl, D. 5.2% NaOCl
A: 0.5% NaOCl
Answer: A: 0.5% NaOCl 
Explanation: NaOCl as a buffered 0.5% solution was recommended for irrigation of wound during world war I by Dakin. Coolidge introduced NaoCl to endodontics.