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 formocresol, ratio of formalin to cresol: 
Select and explain. 
A. 3:02, B. 2:03, C. 1:02, D. 2:01
C: 1:02
Answer: C: 1:02 
Explanation: Formocresol is a solution of 19% formaldehyde, 35% cresol in a vehicle of 15% glycerine and water. To prepare a 1:5 concentration of this formula, first thoroughly mix 3 parts of glycerin with 1 part of distilled waler, then add 4 parts of this preparation to 1 part Buckley’s formocresol, and thoroughly mix again.
Key Concept
In formocresol, we use 19% formaldehyde and 35% cresol i.e. ratio of 1:2.