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
Loss of tooth Length of Premolar in case of orthodontic treatment? 
Select and explain. 
A. 1.0 mm, B. 1.5 mm, C. 2.0 mm, D. 2.5 mm
B: 1.5 mm
Answer: B: 1.5 mm 
Explanation: None