This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bile duct, Subject name: Surgery
The treatment of choice for an 8 mm retained common bile duct (CBD) stone is: 
Select and explain. 
A. Laparoscopic CBD exploration, B. Percutaneous stone extraction, C. Endoscopic stone extraction, D. Extracorporeal shock wave lithotripsy
C: Endoscopic stone extraction
Answer: C: Endoscopic stone extraction 
Explanation: Treatment of Choledocolithiaisis Stone <1.5 cm --ERCP + Stone Removal ERCP is both diagnostic and therapeutic as stenting procedures may be done to allete the obstruction. Stone >1.5cm - Choledochotomy When distal obstruction is suspected- Choledochoduodenostomy