The best answer is D. (Nucleus and Ribosomes)
In the nucleus, information for a particular protein is copied
(transcribed) from DNA to messenger RNA (mRNA).
mRNA then leaves the nucleus and enters the cytoplasm where it
attaches to a ribosome. Transfer RNA in the cytoplasm then begins to
read (translate) the information on the attached mRNA, and, corresponding to
this information, fetches amino acids (from the pool of free amino
acids found in the cytoplasm) and brings them to the ribosome where they are
linked into a chain, forming the primary structure of the protein.
