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
What is the difference between gingivitis and periodontitis? 
Select and explain. 
A. Gingival sutcus., B. Periodontal pocket., C. Loss of epithelial attachment, D. Mobility of tooth
C: Loss of epithelial attachment
Answer: C: Loss of epithelial attachment 
Explanation: None