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: Medicine
[{'content': 'Specific role of endoplasmic reticulum \nSelect and explain. \nA. Lipid biosynthesis, B. Lipid catabolism, C. Maintenance of calcium store, D. Pentose phosphate pathway', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]