The correct option is B ribosomes
There are two basic types of endoplasmic reticulum (ER) - Rough ER and the smooth ER. Both rough ER and smooth ER have the same types of membranes but they have different shapes. Rough ER looks like sheets or disks of bumpy membranes while smooth ER looks more like tubes. Rough ER is called rough because it has ribosomes attached to its surface. It is involved in protein synthesis. Smooth ER is involved in lipid metabolism.