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
Cutting efficiency is best with which of the following materials? 
Select and explain. 
A. Carbide, B. Stainless steel, C. Carbon steel, D. Cobalt-chromium alloys
A: Carbide
Answer: A: Carbide 
Explanation: Hand instrument are made of stainless steel, carbon steel, or blades of tungsten carbide soldered to a steel handle. Carbon steel is able to keep a cutting edge better than stainless steel.
Carbide blades, however, are the most efficient in cutting, even though they are somewhat brittle.
Ref: Operative dentistry modern theory and practice Marzouk page 59