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 not found in commercially 
available tooth paste? 
Select and explain. 
A. Humectants, B. sweetening agents, C. detergents, D. astringent
D: astringent
Answer: D: astringent 
Explanation: None