What is the primary function of the promoter in transcription?

The primary function of the promoter in transcription is to designate the template strand where transcription begins. The promoter is a specific DNA sequence located near the start of a gene that provides a binding site for RNA polymerase and other transcription factors. This facilitates the initiation of transcription, ensuring that the RNA polymerase correctly identifies which strand of the DNA will be used as the template for synthesizing RNA.

A promoter does not signal termination of transcription; that role is instead performed by specific sequences called terminators. Furthermore, while RNA polymerase does interact with the promoter, it is not involved in binding for replication, which is the role of DNA polymerase. Lastly, while the promoter is crucial in initiating transcription, it does not encode the RNA sequence itself; that function is associated with the coding region of the gene downstream of the promoter. Thus, option C correctly identifies the role of the promoter in initiating the transcription process.