Answer:

A.UAU

Explanation:

In mRNA,the sequence can be completed just by encoding the complement of the base in the antisense strand or template strand of the chosen DNA region.In this case,the DNA template reads "ATA".The complement of adenine is supposed to be T or thymine,but in mRNA,it is is replaced by Uracil.Next,the complement of thymine is A or adenine,and adenine is complement with Uracil.All in all,the sequence in mRNA is "UAU".