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': '6 membered ring structure of monosaccharides are known as: \nSelect and explain. \nA. Pyran, B. Furan, C. Aldose, D. Ketose', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The ring structures of monosaccharides are similar to the ring structures of either pyran (a six-membered ring) or furan (a five-membered ring). For glucose in solution, more than 99% is in the pyranose form. Ref: Harper 28th edition, chapter 14.', 'role': 'assistant'}]