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
Under normal condition amount of fluoride secreted from the gland in the mouth: 
Select and explain. 
A. 0.007-0.05ppm, B. 0.005-0.007ppm, C. 0.07-0.05ppm, D. None.
A: 0.007-0.05ppm
Answer: A: 0.007-0.05ppm 
Explanation: None