Fill in the blank: transcription factors (proteins) our cells to promote gene expression (e. g., the production of insulin) by binding directly to dna and by assisting to initiate transcription.
a. actin monomers
b. tight junctions
c. rna polymerases
d. muscle fibrils

The correct answer will be option-C.

Explanation:

The RNA polymerase is the enzyme which synthesizes the mRNA molecules using a single strand of DNA.  RNA polymerase has the ability to bind nucleotide at 3' end of the strand thus proceeding the strand in 5' to 3' direction.

In the given question, gene expression of the insulin-producing gene has been discussed which uses transcription factors. The transcription factors assist RNA polymerase enzyme to attach to the promoter sequence and start synthesizing RNA molecule.

Thus, Option-C is the correct answer.

i think that the best answer would be c.

tell me if im wrong : )

your answer is "the 1950's"