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
The procedure of choice for elective removal of CBD stones for most patients is - 
Select and explain. 
A. Open choledocholithotomy, B. Endoscopic papillotomy, C. Laparoscopic choledocholithotomy, D. Percutaneous choledocholithotomy
B: Endoscopic papillotomy
Answer: B: Endoscopic papillotomy 
Explanation: • ERCP: Diagnostic and therapeutic test of choice for patients with suspected CBD stones
• CBD stones are classified by point of origin
• Found in 6–12% of patients with GB stones
• Retained stones discovered within 2 years of cholecystectomy
• Recurrent stones detected >2 years following cholecystectomy
• ERCP: Diagnostic and therapeutic test of choice for patients with suspected CBD stones.
Treatment
• Treatment options are ERCP, laparoscopic or open CBD Exploration.