This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Pigment gallstones usually not seen in: 
Select and explain. 
A. Gilbe's syndrome, B. Alcoholic cirrhosis, C. Cystic fibrosis, D. Clofibrate therapy
D: Clofibrate therapy
Answer: D: Clofibrate therapy 
Explanation: Clofibrate therapy: Increased biliary secretion of cholesterol, leads to cholesterol gallstones. Pigment stones are more common in patients who have chronic hemolytic states), liver cirrhosis, Gilbe's syndrome, or cystic fibrosis. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 2618