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
Hardness of which of the following abrasives is maximum? 
Select and explain. 
A. Sand, B. Emery, C. Boron carbide, D. Silicon carbide
C: Boron carbide
Answer: C: Boron carbide 
Explanation: Diamond called as super abrasive>boron carbide> silicon carbides