Answer:
It is double stranded DNA, and it could be from an eukaryote, a prokaryote or a virus.
Explanation:
You can rule out the possibility of the nucleic acid being RNA because of the presence of thymine, which is absent in RNA, and is replaced by the base Uracil. In double stranded DNA, guanine pairs with cytosine, and thymine pairs with adenine, so the proportions of A and T, as well as those of C and G, should be the same. This is consistent with the information given, so you can conclude that it is indeed double stranded (this can also be concluded simply by the fact that it is DNA, because this type of nucleic acid is always double stranded).
All types of organisms can have a DNA genome, so it could either belong to eukaryotes, prokaryotes, or viruses. If it were RNA, it would only be possible for it to belong to a virus, since they are the only ones that can have an RNA genome.