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
In a patient with sponteneous biliary enteric fistula the most common site of communication with gall bladder is 
Select and explain. 
A. Duodenum, B. Jejunum, C. Ileum, D. Transverse colon
A: Duodenum
Answer: A: Duodenum 
Explanation: .BILIARY FISTULAS - Types a. External: Usually occurs as a complication of surgery following-- * Gastrectomy. * Cholecystectomy open or laparoscopic. * CBD surgery. * Pancreatic surgery. b. Internal: * Cholecysto-duodenal fistula causing gallstone ileus. * Cholecysto-enteric fistula. * Cholecysto-choledochal fistula. External biliary fistulas are difficult to manage, often dangerous, but many a times resolve spontaneously. ref:SRB&;s manual of surgery,ed 3,pg no 593