What role does RNA polymerase play during transcription?

During transcription, RNA polymerase is essential for synthesizing RNA from a DNA template. Specifically, RNA polymerase binds to the DNA at a promoter region and catalyzes the assembly of nucleotides into a complementary RNA strand. This involves reading the DNA sequence and creating a single-stranded RNA molecule that matches the sequence of the DNA template, substituting uracil for thymine.

RNA polymerase initiates transcription by unwinding the DNA double helix, but its primary role is to catalyze the formation of the RNA molecule, linking together RNA nucleotides in the correct order as dictated by the DNA sequence. This makes option C the correct choice regarding RNA polymerase's function in transcription.