Which of the following descriptions about DNA and RNA polymerase are correct: A: RNA polymerase synthesize RNA chain using nucleoside diphosphate instead of nucleoside triphosphates. B: RNA polymerase can initiate transcription without a primer, and nucleotides are added to 5’ end of the growing RNA chain. C: RNA polymerase can add nucleotides in both 3’ or 5’ end of RNA chain. D: Both RNA polymerase and DNA polymerase can only add nucleotides to 3’ end of the polynucleotides.