What happens during the processing of an RNA molecule?

During the processing of an RNA molecule, particularly in eukaryotic cells, the primary transcript undergoes several modifications to become a mature messenger RNA (mRNA). Introns—non-coding regions that do not contribute to the protein-coding sequence—are removed from the RNA molecule. This process is known as splicing. Following the removal of introns, the exons, which are the coding sequences, are spliced together to form a continuous coding sequence that can then be translated into a protein.

This processing is essential because it ensures that only the necessary coding sequences are present in the mature mRNA, allowing for accurate protein synthesis during translation. Thus, the correct understanding of RNA processing highlights the vital role of intron removal and exon joining, which forms the basis of option C being the correct choice.