The correct option is A Protein synthesis
DNA undergoes transcription and produces m-RNA which act as a template for synthesis of proteins.
DNA duplicates itself by the process of replication.
DNA undergoes transcription, which form RNA. Some of the RNA gets folded and form t-RNA.
Protein is indirectly synthesized by DNA. The DNA molecules undergoes transcription to form m-RNA which translates into protein.
So, the correct answer is option A.