Answer:
(C). ribosomes.
Explanation:
The ER (endoplasmic reticulum) can be defined as an eukaryotic cell organelle, which makes interconnected network of membrane-bound, flattened sac-like structures. These structures are known as cisternae
The endoplasmic reticulum can be divided into two types, on the basis of presence or absence of ribosomes. The smooth ER does not ribosomes on its surface, while rough ER carries ribosomes on its surface. These ribosomes are known as protein-manufacturing units of cells.
Thus, the correct answer is option (C).
