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
Specific role of endoplasmic reticulum 
Select and explain. 
A. Lipid biosynthesis, B. Lipid catabolism, C. Maintenance of calcium store, D. Pentose phosphate pathway
A: Lipid biosynthesis
Answer: A: Lipid biosynthesis 
Explanation: None