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
It is normal response to orthodontic treatment for periodontal space to 
Select and explain. 
A. Widen, B. Narrow, C. Shorten, D. Elongate
A: Widen
Answer: A: Widen 
Explanation: None