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
[{'content': 'In formocresol, ratio of formalin to cresol: \nSelect and explain. \nA. 3:02, B. 2:03, C. 1:02, D. 2:01', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Formocresol is a solution of 19% formaldehyde, 35% cresol in a vehicle of 15% glycerine and water. To prepare a 1:5 concentration of\xa0this formula, first thoroughly mix 3 parts of glycerin with 1 part of distilled waler, then add 4\xa0parts of this preparation to 1 part Buckley’s\xa0formocresol, and thoroughly mix again.\nKey Concept\nIn formocresol, we use 19% formaldehyde and 35% cresol i.e. ratio of 1:2.', 'role': 'assistant'}]