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
A single force is applied to the crowns of the upper incisors.
Tipping is around the point of rotation present at: 
Select and explain. 
A. Infinity, B. Apical 1/3rd, C. middle 1/3rd, D. Coronal 1/3rd
B: Apical 1/3rd
Answer: B: Apical 1/3rd 
Explanation: None