This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Which of the following cellular compounds are involved in protein synthesis? 
Select and explain. 
A. Rough endoplasmic reticulum, B. Smooth endoplasmic reticulum, C. Ribosomes, D. Mitochondria
C: Ribosomes
Answer: C: Ribosomes 
Explanation: Rough ER produces proteins that are not expoed, the better answer here would be ribosomes.