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
[{'content': 'All are impoant mechanisms in the formation of lithogenic bile: \nSelect and explain. \nA. Increased biliary secretion of cholesterol, B. Increased activity of HMG CoA reductase, C. Clofibrate, D. Low calorie and cholesterol rich diet', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Mechanisms in the formation of lithogenic (stone-forming) bile. The most impoant is increased biliary secretion of cholesterol. This may occur in association with obesity, the metabolic syndrome, high-caloric and cholesterol-rich diets, or drugs (e.g., clofibrate) and may result from increased activity of hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 2617', 'role': 'assistant'}]