Which of the following characteristics of transcription initiation by 70-containing polymerase holoenzymes is different than for ?54-containing polymerase holoenzymes?

A) The closed complex spontaneously converts to the open complex
B) The formation of the closed complex is readily reversible
C) The opening of the DNA duplex is accompanied by energetically favorable conformational changes in the holoenzyme.
D) The holoenzyme binds to its promoter to initially form a closed complex.
E) The holoenzyme binds to its promoter to initially form a closed complex.