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
The commonest cause of acute pancreatitis is 
Select and explain. 
A. Biliary calculi, B. Alcohol abuse, C. Infective, D. Idiopathic
A: Biliary calculi
Answer: A: Biliary calculi 
Explanation: Major cause of acute pancreatitis is biliary calculi(50-70% of patients) A careful search of aetiology is must before labelling idiopathic and no more than 20% cases should fall into this category. Bailey & Love 26th edition,1127,1128.