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: Biochemistry
[{'content': 'Cholesterol is a (an) \nSelect and explain. \nA. Ester, B. Phospholipid, C. Sterol, D. Lipoprotein', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Sterol\n\nCholesterol is the most important sterol.', 'role': 'assistant'}]