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
Process shown in color plate is: 
Select and explain. 
A. Bleeding on probing., B. Bone sounding., C. Pocket measurement, D. Attached ginigiva measurement
B: Bone sounding.
Answer: B: Bone sounding. 
Explanation: None