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 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: Ans. is 'a' i.e., Biliary calculi