Put the steps of transcription in order.
DNA strands are unwound and separated.
The complementary RNA nucleotides are
RNA polymerase binds to the promoter.
added

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.

i think it’s c but i might be wrong. if i am let me know! have a good rest of your day as well!