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 index used to record the plaque score is 
Select and explain. 
A. PMA Index, B. Silness and Loe Index, C. Green and vermillion Index, D. Russell's index
B: Silness and Loe Index
Answer: B: Silness and Loe Index 
Explanation: None