Answer:
C. Rough
Step-by-step explanation:
When ribosomes are attached to the outer surface of an endoplasmic reticulum it is called rough endoplasmic reticulum. When ribosomes are not attached to the outer surface of an endoplasmic reticulum it is called smooth endoplasmic reticulum. Protein translation takes place at the rough endoplasmic reticulum whereas lipids and hormones are synthesized at the smooth endoplasmic reticulum.