The answer is endoplasmic reticulum. There are two types of the organelle. The rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER). The RER has ribosomes attached to its outer membrane hence mainly folds, modifies and transports proteins. SER, on the other hand, is significant in the modification and transportation of lipids.
It's because everything has a certain place in DNA. every acid or amino acid carries a specific thing or role in DNA period without all three it wouldn't function well.
probably d) but im not 100% sure