This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: vitamins, Subject name: Biochemistry
[{'content': 'Which of the following combinations of biologically active molecules does vitamin A consist of? \nSelect and explain. \nA. Retinol, retinal and retinoic acid, B. Retinol, retinal and tetrahydrofolate, C. Retinol, Iconjugase and retinoic acid, D. PABA, retinal and retinaldehyde', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The term retinoids is often used to include the natural and synthetic forms of vitamin A Retinol, retinal and retinoic acid are regarded as vitamers of vitamin A. beta-Carotene (provitamin A): This is found in plant foods ref Satyanarayana 4th ed page 119', 'role': 'assistant'}]