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
Uniform reduction on the tooth surface may be ensured by the placement of 
Select and explain. 
A. Pins, B. Depth grooves, C. Ledges, D. Bevels
B: Depth grooves
Answer: B: Depth grooves 
Explanation: None