This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
Biliary stricture developing after laparascopic choice cystectomy usually occurs at which pa of the common bile duct 
Select and explain. 
A. Upper, B. Middle, C. Lower, D. All side with equal frequency
A: Upper
Answer: A: Upper 
Explanation: Biliary strictures post cholecystectomy commonly occur in CBD,that too near the confluence of right and left hepatic ducts;.i.e., in the upper pa of CBD. Reference.SRB's manual of surgery,5th edition,page no:658.