Final answer:
The nucleolus is responsible for making ribosomes, which are then transported to the cytoplasm to synthesize proteins. The correct answer is 'C. ribosomes, cytoplasm.'
Step-by-step explanation:
The nucleolus plays a crucial role in protein synthesis by producing ribosomes. Ribosomes are the protein-producing organelles of a cell. After being made in the nucleolus, ribosomes are exported to the cytoplasm, where they direct protein synthesis. Therefore, the correct answer to the question is 'C. ribosomes, cytoplasm.'