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': 'Xylitol is a \nSelect and explain. \nA. Natural sweet amino acid, B. Synthetic sweet amino acid, C. Natural five carbon sugar, D. Synthetic five carbon sugar', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]