In DNA replication many enzymes and proteins are required to replicate a DNA template. For initiation of DNA synthesis the two DNA strands must be separated which is done by helicase.
Then primase adds short nucleotide sequence and initiate DNA replication. After that DNA polymerase acts and adds nucleotide at the 3' end of growing DNA strand. Ligase is the enzyme that joins the two Okazaki fragments that are created in the lagging strand.
RNA polymerase is not required in DNA replication and it works in transcription therefore the correct answer is RNA polymerase.
DNA polymerase, primase, helicase, and ligase are all enzymes required by cell for DNA replication. RNA polymerase is an enzyme for RNA synthesis and not DNA.
