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
In Snyder's Test, the saliva is said to be highly cariogenic
if colour change is observed at (hrs) 
Select and explain. 
A. 24, B. 48, C. 72, D. 96
A: 24
Answer: A: 24 
Explanation: None