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
[{'content': 'The availability for orthodontic treatment depends on \nSelect and explain. \nA. Severity & extent of periodontal lesions, B. Amount of bone available, C. Prognosis of periodontal lesions without ortho treatment, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]