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
After examining a patient for periodontal problem using Russets index you have a meanscore of 3. It indicates: 
Select and explain. 
A. Established periodontal disease, which is reversible, B. Established periodontal disease that is irreversible, C. Beginning of periodontal disease, D. Terminal periodontal disease
B: Established periodontal disease that is irreversible
Answer: B: Established periodontal disease that is irreversible 
Explanation: None