Answer:
The correct answer would be AUCAUCAUC.
It can be explained with the help of the complementary nature of the mRNA and template strand of the DNA.
It means that the nucleotide sequence of the DNA template strand is complementary to the nucleotide sequence of the mRNA.
The complementary bases are guanine and cytosine; adenine and thymine.
In addition, in mRNA uracil is used in place of thymine.
Thus, if the nucleotide sequence of the DNA is TAGTAGTAG, then the nucleotide sequence of the mRNA would be AUCAUCAUC.