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': 'Which index uses calibrated probe for calculus? \nSelect and explain. \nA. OHI, B. Marginal line calculus index, C. Calculus severity index, D. Volpe Manhold Index', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]