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 cells are decreased in chronic periodontitis? 
Select and explain. 
A. B-lymphocytes, B. T-lymphocytes, C. Mast cells, D. Plasma cells
B: T-lymphocytes
Answer: B: T-lymphocytes 
Explanation: None