Final answer:
Eukaryotic RNA polymerases require transcription factors to bind DNA promoters and initiate transcription, unlike enhancers and silencers that modulate efficiency.
Step-by-step explanation:
Eukaryotic RNAPs cannot bind DNA promoters without the help of other proteins. The correct answer to the question is c) Transcription factors, which are crucial for the formation of a preinitiation complex on the DNA template that subsequently recruits RNA polymerase II for transcription initiation. Unlike enhancers and silencers, which affect transcription efficiency, transcription factors are essential for the transcription initiation process. These factors include a range of proteins, one of which is TFIID that comprises the TATA-binding protein that initially binds to the promoter. Subsequently, other transcription factors and protein complexes assemble to stabilize this pre-initiation complex, enabling the binding of RNA polymerase II to begin transcription.