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 W.H.O. periodontal probe (CPITN probe) has a black color coded rings \nSelect and explain. \nA. 0 to 0.5 mm, B. 3 to 3.5 mm, C. 8.5 to 11.5 mm, D. 3 to 5 mm', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]