A student titrates a sample of a weak diprotic acid, \(\text{H}_2\text{A(aq)}\), with standard \(0.10\text{ M }\text{NaOH(aq)}\). The acid has ionization constants \(K_{a1} = 1.0 \times 10^{-4}\) and \(K_{a2} = 1.0 \times 10^{-9}\). Exactly one stoichiometric equivalent of \(\text{NaOH(aq)}\) is added, reaching the first equivalence point of the titration according to the following equation:

\[ \text{H}_2\text{A(aq)} + \text{OH}^-\text{(aq)} \rightarrow \text{HA}^-\text{(aq)} + \text{H}_2\text{O(l)} \]

Which of the following correctly identifies the predominant A-containing species in the resulting solution and its acid-base role?