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: Surgery
In lag screw technique, what is the function of counter-sink? 
Select and explain. 
A. Assures appropriate receptacle for screw head, B. It is the hole made in the distal fragment that engages the screw threads, C. It is the hole made in the proximal segment that does not engage the screw threads, D. It is non functional
A: Assures appropriate receptacle for screw head
Answer: A: Assures appropriate receptacle for screw head 
Explanation: To flush the obliquely place screw head with the rest of the proximal cortex, countersink is made that acts as a receptacle for engaging the end of screw head.