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 preferred bypass procedure in case of non resectable carcinoma of head of pancreas is? 
Select and explain. 
A. Cholecystojejunostomy, B. Cholecystogastrostomy, C. Choledochoduodenostomy, D. Choledochojejunostomy
A: Cholecystojejunostomy
Answer: A: Cholecystojejunostomy 
Explanation: Ans. is 'a' i.e., Cholecystojejunostomy