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 W.H.O. periodontal probe (CPITN probe) has a black color coded rings 
Select and explain. 
A. 0 to 0.5 mm, B. 3 to 3.5 mm, C. 8.5 to 11.5 mm, D. 3 to 5 mm
C: 8.5 to 11.5 mm
Answer: C: 8.5 to 11.5 mm 
Explanation: None