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
The availability for orthodontic treatment depends on 
Select and explain. 
A. Severity & extent of periodontal lesions, B. Amount of bone available, C. Prognosis of periodontal lesions without ortho treatment, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: None