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 plaque is primary 
Select and explain. 
A. Calcium and fluoride, B. Calcium and sodium, C. Calcium and phosphorus, D. Sodium and calcium
C: Calcium and phosphorus
Answer: C: Calcium and phosphorus 
Explanation: None