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
Most commonly used technique of flossing? 
Select and explain. 
A. Spool method, B. Spiral method, C. Winding method, D. Knutson method
A: Spool method
Answer: A: Spool method 
Explanation: None