Answer:
B
Explanation:
Transcription, which occurs in the nucleus, is the first process of protein synthesis. Transcription involves making a complementary strand of mRNA from a DNA template. The mRNA serves a a carrier of the genetic information originally stored in DNA out of the nucleus into the cytoplasm, where translation occurs.
Transcription occurs when an enzyme called RNA polymerase binds to the region of a gene called PROMOTER region, causing the DNA strand to unwind and ultimately builds the mRNA molecule using complementary base pairs.
N.B: Complementary base pairing rule is the phenomenon where in DNA, Adenine (A) always binds to Thymine (T) in an hydrogen bonding and Guanine (G) always binds to Cytosine (C) with the same bond. It is important to note that in the newly made RNA molecule, all the Thymine (T) nucleotides is replaced by Uracil (U).
During transcription, the DNA of a gene serves as a template for complementary base pairing, in which RNA polymerase synthesizes a complementary strand of the nucleotide it reads e.g. if it reads Adenine in the DNA, it adds Uracil to the attached RNA molecule.
For example, a DNA nucleotide that reads AGGCTGA will be read by RNA polymerase, and it will synthesize a complementary strand of mRNA having the nucleotide UCCGACU.
