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
Gall stone can be which type of stone? 
Select and explain. 
A. Triple phosphate stone, B. Oxalate stone, C. Cholesterol stone, D. Urate stone
C: Cholesterol stone
Answer: C: Cholesterol stone 
Explanation: 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.