Which of the following is a type of endoplasmic reticulum?

The endoplasmic reticulum is a network of membranous tubules within the cytoplasm of eukaryotic cells that is continuous with the nuclear membrane. It is classified into two types: the rough endoplasmic reticulum (rough ER) and the smooth endoplasmic reticulum (smooth ER). The rough endoplasmic reticulum (RER) is studded with ribosomes and is involved in protein synthesis, folding, and transport. Smooth endoplasmic reticulum (SER) lacks ribosomes and is involved in lipid synthesis, carbohydrate metabolism, and detoxification.