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': 'Range of OHI is: \nSelect and explain. \nA. 0-4, B. 3-Jan, C. 0-6, D. 0-12', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The Oral Hygiene Index (OHI) was developed in 1960 by John C. Greene and Jack R. Vermillion to classify and assess oral hygiene status.\nTo calculate the OHI, the DI and CI are summed: OHI = DI + CI\xa0\nThe DI and CI values range from 0 to 6.\nOHI value ranges from 0 to 12.\n\nEssentials of preventive and community dentistry\nSoben Peter\n5th edition\npage no. 318', 'role': 'assistant'}]