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
The indicators of the periodontal disease status measures all of the following by using CPI index in oral health surveys EXCEPT: 
Select and explain. 
A. Bleeding, B. Bone loss, C. Calculus, D. Periodontal pocket
B: Bone loss
Answer: B: Bone loss 
Explanation: None