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
A compound PDL pocket is 
Select and explain. 
A. Spiral type, B. Present on 2 or more surfaces, C. Infrabony in nature, D. All of the above
B: Present on 2 or more surfaces
Answer: B: Present on 2 or more surfaces 
Explanation: None