Final answer:
RNA polymerase II is responsible for synthesizing mRNA in eukaryotic cells. It initiates transcription and elongates the mRNA transcript by forming phosphodiester bonds.c. RNA Polymerase II
Step-by-step explanation:
RNA polymerase II is responsible for synthesizing mRNA in eukaryotes. It is one of the three RNA polymerases found in eukaryotic cells, with RNA polymerase I synthesizing rRNA and RNA polymerase III synthesizing tRNA and 5S rRNA. RNA polymerase II initiates transcription at a promoter sequence and catalyzes the formation of phosphodiester bonds to elongate the mRNA transcript.