This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Classification of carbohydrate, Subject name: Biochemistry
[{'content': 'Which of the following glycosaminoglycan contains iduronic acid? \nSelect and explain. \nA. Hyaluronic acid, B. Keratan sulfate I, C. Keratan sulfate II, D. Heparin', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Option d : Heparin contains iduronic acid Glucuronic acid is the hexuronic acid present in most of the glycosaminoglycans. Iduronic acid is a component of Heparin Dermatan sulfate Heparin and Heparan sulfate both contain N-sulfo glucosamine sugar instead of N-acetyl glucosamine as sugar component. NOTE: Dermatan sulfate is made up of N-acetyl galactosamine + iduronic/glucuronic acid', 'role': 'assistant'}]