The correct answer is Endoplasmic Reticulum. After the amino acid chain leaves the ribosome, it is transported to the endoplasmic reticulum, where it undergoes folding and modification. The endoplasmic reticulum is responsible for quality control and properly folding the protein into its functional three-dimensional structure. It can also modify the protein by adding sugars or lipids to it. Once the protein is correctly folded and modified, it is then transported to its final destination within the cell or to the cell membrane for secretion.
