The correct answer is D. Cytoplasm.
Ribosomes are small organelles found in the cytoplasm of cells. They are responsible for protein synthesis, which is the process of building proteins from amino acids. Ribosomes are made up of two subunits, a large subunit and a small subunit. The large subunit is made up of 54 proteins and 4 rRNAs, while the small subunit is made up of 33 proteins and 1 rRNA. The two subunits come together to form a functional ribosome when they are attached to a messenger RNA (mRNA). The mRNA contains the code for the protein that is to be synthesized. The ribosome reads the code on the mRNA and uses it to assemble the amino acids into the correct order to form the protein.
The nucleus is the control center of the cell. It contains the cell’s DNA, which is the blueprint for the cell’s proteins. The DNA is transcribed into RNA, which is then used by the ribosomes to synthesize proteins.
The vacuole is a membrane-bound organelle that is found in plant cells. It stores water, nutrients, and waste products.
The endoplasmic reticulum is a network of tubules and sacs that is found in the cytoplasm of cells. It is involved in the synthesis of proteins, lipids, and carbohydrates.