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
Which of the following bone defects offers the best chance for bone fill? 
Select and explain. 
A. 3 Walled defect, B. 2 Walled defect, C. Osseous crater, D. Hemisepta
A: 3 Walled defect
Answer: A: 3 Walled defect 
Explanation: None