The following pictures represent solutions at various points in the titration of a weak acid HA with aqueous NaOHNaOH. (Na+Na+ ions and solvent water molecules have been omitted for clarity.) Which picture corresponds to each of the following points in the titration? (a) Before the addition of any NaOHNaOH (b) Before the equivalence point (c) At the equivalence point (d) After the equivalence point