This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET 2019, Subject name: Biochemistry
Which type of cholesterol is present in gall stones? 
Select and explain. 
A. Amorphous cholesterol dihydrate, B. Amorphous cholesterol monohydrate, C. Crystalline cholesterol dihydrate, D. Crystalline cholesterol monohydrate
D: Crystalline cholesterol monohydrate
Answer: D: Crystalline cholesterol monohydrate 
Explanation: Gallstones are composed: Principally of cholesterol monohydrate crystals or Acid salt of calcium bilirubinate.