Which letters represent the names of bases in DNA and mRNA?

The correct identification of the bases in DNA and mRNA is represented by the sequence A, G, C, T, U. In DNA, the bases are adenine (A), guanine (G), cytosine (C), and thymine (T). When it comes to mRNA, it has the same bases as DNA, except that thymine is replaced by uracil (U). Thus, when referring to the bases found in both DNA and mRNA, we can list them altogether: A, G, C (which are common in both), T (specific to DNA), and U (specific to RNA).

This reasoning highlights why "A, G, C, T, U" is the correct selection, as it effectively captures the complete range of nucleotide bases found in both nucleic acids, with consideration of their unique as well as common bases.