Final answer:
The correct answer is b. RNA polymerase dissociates. Hence, b) is correct.
Step-by-step explanation:
The correct answer is b. RNA polymerase dissociates. Before a eukaryotic mRNA is exported from the nucleus, several modifications occur, including the addition of a 5' cap, splicing out of introns, and polyadenylation at the 3' end.
However, the dissociation of RNA polymerase from the DNA template occurs during transcription, not during mRNA export.