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
Classification of bony defects are most helpful in
determining the likelihood of repair after periodontal treatment is based on 
Select and explain. 
A. Depth of bone defect, B. Number of bone walls remaining, C. Distance between the facial, lingual walls, D. Distance from the crest of defect to CEJ
B: Number of bone walls remaining
Answer: B: Number of bone walls remaining 
Explanation: None