Final answer:
The unprocessed form of messenger RNA is called pre-mRNA, which undergoes various processing steps like capping, splicing, and polyadenylation to become mature mRNA ready for protein synthesis.
Step-by-step explanation:
The initial, unprocessed form of messenger RNA (mRNA) is known as pre-mRNA or precursor messenger RNA. Therefore, the correct answer to the question is c) pre-mRNA (precursor messenger RNA).
In eukaryotic cells, pre-mRNA undergoes several processing steps before it becomes mature mRNA that can be translated into a protein. This processing of mRNA includes the addition of a 5' cap and a poly-A tail to protect the RNA from degradation, as well as the removal of non-coding regions known as introns through a process called splicing. The resulting mRNA carries the genetic code from DNA to the ribosome, where protein synthesis takes place.