Which one of the following is not the function of endoplasmic reticulum?

The Endoplasmic Reticulum (ER) is a large network of membrane-bound tubes and sheets. It exists in two forms: Rough ER (RER), which is involved in the synthesis of proteins due to attached ribosomes, and Smooth ER (SER), which is responsible for the synthesis of lipids and steroid hormones. Some of these proteins and lipids are used for membrane biogenesis (the formation of the cell membrane). However, the packaging, modification, and sorting of materials into vesicles for delivery to various targets inside and outside the cell is the primary function of the Golgi apparatus. Therefore, option B is not a function of the endoplasmic reticulum.