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': 'Which of the following plays an important role in retinol mobilization? \nSelect and explain. \nA. Zinc, B. Iron, C. Manganese, D. Magnesium', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Zinc\xa0plays\xa0an\xa0important\xa0role\xa0in\xa0retinol mobilization.', 'role': 'assistant'}]