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': 'Retinol is a primary alcohol containing:- \nSelect and explain. \nA. Alpha-ionone ring, B. Beta-ionone ring, C. One isoprenoid unit, D. Two double bonds', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Retinol (vitamin A alcohol):\xa0\n\nlt is a primary alcohol containing beta-ionone ring.\xa0\nThe side chain has two isoprenoid units, four double bonds and one hydroxyl group.\xa0\nRetinol is present in animal tissues as retinyl ester with long chain fatty acids\n\nKey Concept:\nRetinol is a vitamin A (alcohol containing beta-ionone ring)', 'role': 'assistant'}]