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
Maximum amount of incisor retraction achieved is: 
Select and explain. 
A. 7 mm, B. 16 mm, C. 9 mm, D. 26 mm
A: 7 mm
Answer: A: 7 mm 
Explanation: None