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
Intrabony pockets are given a score of ___________ in
Russell's periodontal index: 
Select and explain. 
A. 3, B. 4, C. 6, D. 8
D: 8
Answer: D: 8 
Explanation: None