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: Anatomy
Which of the following is the most common non-alcoholic cause of acute pancreatitis 
Select and explain. 
A. Thiazides, B. Hypercalcaemia, C. Gall stones, D. Hyperlipidaemia
C: Gall stones
Answer: C: Gall stones 
Explanation: Gallstones are hardened deposits of digestive fluid. Gallstones can vary in size and number and may or may not cause symptoms. People who experience symptoms usually require gallbladder removal surgery. Gallstones that don't cause symptoms usually don't need treatment Ref : Oxford textbooks of surgery 2nd/e p. 1766