Explanation:
In a DNA molecule, Adenine forms hydrogen bonds with Thymine and Cytosine forms hydrogen bomds with Guanine.
However in mRNA, Thymine becomes Uracil (T => U)
Therefore every A in the DNA sequence becomes U,
every T in the DNA sequence becomes A,
every C in the DNA sequence becomes G,
every G in the DNA sequence becomes C.
The answer is A.
