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
Which of the following is true about tooth associated subgingival plaque? 
Select and explain. 
A. Has both gram positive and negative bacteria, B. Extends till the junctional epithelium, C. May penetrate cementum, D. Associated with gingivitis and periodontitis
C: May penetrate cementum
Answer: C: May penetrate cementum 
Explanation: None