Answer:
A poly-A tail.
Explanation:
Transcription may be defined as the process of formation of the RNA molecules from the DNA template. Eukaryotic RNA undergoes the process of mRNA processing.
The mRNA processing involves the post translation modification of RNA. The poly A (adenine) tail is added to the 3' end of the RNA transcript after the elongation. This poly A tail protects the RNA from the degradation and helps to export the RNA into the cytoplasm.
Thus, the correct answer is option (a).
