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 inorganic component of subgingival plaque is derived from 
Select and explain. 
A. Saliva, B. Gingival crevicular fluid, C. Inorganic matter of tooth, D. Food debris
B: Gingival crevicular fluid
Answer: B: Gingival crevicular fluid 
Explanation: None