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
[{'content': 'Gall stone can be which type of stone? \nSelect and explain. \nA. Triple phosphate stone, B. Oxalate stone, C. Cholesterol stone, D. Urate stone', 'role': 'user'}, {'content': "Answer: C \nExplanation: Cholesterol stones (cholesterol solitaire-radiating crystal line appearance) are formed when bile's supersaturated with cholesterol or bile acid concentrations are low.80% of gallstones are cholesterol/mixed stones in USA & Europe,whereas in Asia 80% are pigment stones.Cholesterol/mixed stones contain 51-99% pure cholesterol plus an admixture of calcium salts,bile acids,bile pigments & phospholipids. Reference:Bailey & Love's manual of surgery,25th edition,page no:1120.", 'role': 'assistant'}]