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 young permanent teeth the best method of sensitivity testing for traumatized teeth is Carbondioxide snow which can go up to temperature of 
Select and explain. 
A. —20°C, B. —30°C, C. —40°C, D. —78°C
D: —78°C
Answer: D: —78°C 
Explanation: None