Final answer:
Option 1: Transcription. Transcription is the process of copying a nucleotide sequence of DNA to form a complementary strand of mRNA.
Step-by-step explanation:
Transcription is the process of copying a nucleotide sequence of DNA to form a complementary strand of mRNA. It occurs in the nucleus of the cell. The process involves the enzyme RNA polymerase binding to a specific region of DNA called the promoter. The RNA polymerase then separates the DNA strands and uses one strand as a template to synthesize a complementary mRNA strand. The mRNA is formed by joining together nucleotides that are complementary to the DNA template strand. For example, Adenine (A) in DNA pairs with Uracil (U) in mRNA.