This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood, Subject name: Pathology
[{'content': 'Gall stones in sickle cell anemia are made up of? \nSelect and explain. \nA. Cholesterol, B. Calcium carbonate, C. Bilirubin, D. None', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e. Bilirubin * In sickle cell disease, chronic hemolysis with its accelerated bilirubin turnover leads to a high incidence of pigment gallstones. They are composed primarily of bilirubin (insoluble bilirubin pigment polymer) and calcium (calcium phosphate) salts that are found in bile.", 'role': 'assistant'}]