This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of protein and amino acid, Subject name: Biochemistry
[{'content': 'Non-protein nitrogen product in food \nSelect and explain. \nA. Sucrose, B. Triglyceride, C. Urea, D. Cholesterol', 'role': 'user'}, {'content': 'Answer: C \nExplanation: NPN refers to all N2containing substances other than proteins. include urea, uric acid, creatinine.', 'role': 'assistant'}]