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
[{'content': 'The indicators of the periodontal disease status measures all of the following by using CPI index in oral health surveys EXCEPT: \nSelect and explain. \nA. Bleeding, B. Bone loss, C. Calculus, D. Periodontal pocket', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]