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: Pathology
All of the following are cariogenic substances except: 
Select and explain. 
A. Selenium., B. Vanadium., C. Lead., D. Magnesium.
B: Vanadium.
Answer: B: Vanadium. 
Explanation: None