The correct option is A Transcription
DNA directed synthesis of mRNA is called transcription. Transcription is when RNA is made from DNA. During transcription, RNA polymerase makes a copy of a gene from the DNA to mRNA as needed. This process is similar in eukaryotes and prokaryotes. One difference, however, is that eukaryotic RNA polymerase associates with mRNA-processing enzymes during transcription so that processing cank proceed quickly after the start of transcription.