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
Which of the following is not the function of smooth endoplasmic reticulum? 
Select and explain. 
A. Lipid synthesis, B. Protein synthesis, C. Metabolism of drugs, D. Supply of calcium for cellular functions
B: Protein synthesis
Answer: B: Protein synthesis 
Explanation: None