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
Supplementary retention on the abutment tooth is made
possible by: 
Select and explain. 
A. Greater bulk of metal, B. Proper cementation technique, C. Shoulder preparation, D. Proper use of pins and grooves
D: Proper use of pins and grooves
Answer: D: Proper use of pins and grooves 
Explanation: None