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 PHP index is designed to 
Select and explain. 
A. Evaluate plaque and calculus on specific tooth surfaces, B. Score plaque on specific tooth surfaces, C. Scores plaque and gingivitis, D. Scores plaque, calculus, gingivitis
B: Score plaque on specific tooth surfaces
Answer: B: Score plaque on specific tooth surfaces 
Explanation: None