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
Purulent exudation from the gingival sulci is an indication of: 
Select and explain. 
A. Deep pockets, B. Severe periodontal attachment loss, C. Nature of the inflammatory changes in the pocket wall, D. Shallow pockets
C: Nature of the inflammatory changes in the pocket wall
Answer: C: Nature of the inflammatory changes in the pocket wall 
Explanation: None