Greatest sequence similarity from comparisons of the two (human and mouse gene)

If someone could help me understand the answer to this question, it would be greatly appreciated!

You have identified a previously known human gene that appears to have a role in ADHD. It is similar enough in DNA sequence to a known mouse gene that you believe the two genes may be evolutionarily related. You determine and compare the DNA sequences, the predicted mRNA sequences, and the predicted amino acid sequences corresponding to the two genes. You would expect to find the greatest sequence similarity from comparisons of the two:
A. DNA sequences
B. mRNA sequences
C. Amino acid sequences
D. All three comparisons are likely to show the same degree of sequence similarity.

Post Merge: 9 years ago

I think it would be similar in DNA sequence and up to the amino acid sequence, but not necessarily mRNA sequence?