what is the source of energy that drives transcription elongation forward? choose one: a. the hydrolysis of atp by the general transcription factors associated with rna polymerase b. the breaking of hydrogen bonds as the dna double helix is pried apart c. the phosphorylation of the tail of rna polymerase d. the energy of atp formation e. the hydrolysis of high-energy bonds of ribonucleoside triphosphates