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
If a patient had 28 teeth and 20% of sites has attachment loss, the number of periodontally involved sites will be 
Select and explain. 
A. 112, B. 28, C. 20, D. 22
D: 22
Answer: D: 22 
Explanation: None