Answer:
The correct answer is: Transcription.
Step-by-step explanation:
Transcription is a process that takes place in the nucleus in order to get one RNA sequence from a gene that will code for a specific protein.
Transcription consists of separating the two strands of DNA and using one as a guide to synthesize its complementary strand. In order to save the differences between DNA and RNA, some nucleotides will be changed: thymine in DNA is analog to uracil in RNA.
This complementary strand will be a RNA strand that, after a few modifications, will be ready to be used in Translation (the synthesis of a protein that occurs outside the nucleus).
The enzyme responsible for the synthesis of this RNA strand is RNA Polymerase.
Even though most of the time it is assumed that every RNA strand produced in Transcription is an mRNA, these strands can also be other types of RNA, like tRNA or rRNA.