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 active ingredient present in Tartar control tooth paste is: 
Select and explain. 
A. Pyrophosphate, B. Metaphosphate, C. Carboxy methyl, D. Bi-carbonate
A: Pyrophosphate
Answer: A: Pyrophosphate 
Explanation: None