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
CADIA System is used to check? 
Select and explain. 
A. Progression of Periodontal Disease, B. Mobility of Teeth, C. Furcation Involvement, D. Bleeding Sites
A: Progression of Periodontal Disease
Answer: A: Progression of Periodontal Disease 
Explanation: None