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 key feature that differentiates stage III gingivitis from the stage II lesion is an increase in the number of 
Select and explain. 
A. Lymphocytes, B. Plasma cells, C. Mast cells, D. Polymorphs
B: Plasma cells
Answer: B: Plasma cells 
Explanation: None