The correct answer is: c. Mitochondria and d. Rough ER
Protein disulfide bonds are the links between the sulfur atoms of two cysteine amino acids of the protein and these bonds are part of the secondary and tertiary structure of proteins. Formation of disulfide bonds is very important for the folding and stability of some proteins. Disulfide bonds are mostly found in secretory proteins and lysosomal proteins because of their unstable state in cytosol.
