ER is is an organelle in a cell, specifically eukaryotic cells. The primary difference is that RER contain ribosomes on its surface while SER does not.
The RER are most dense around the Golgi apparatus and nucleus of a cell. The ribosomes found on them are responsible for the assembly of proteins aka translation.
SER are located near the cell periphery and make cellular products like hormones and lipids.
explanation: the reason being is that a, c, and d are why you should eat healthy but b just is the odd one out. i had someone ask me this be4 and i got it correct.