To determine the formula of sodium gallate with gallium having an oxidation state of +3, we need to consider the charges of the ions involved.

Sodium Ion (Na+) Charge: +1

Gallate Ion (GaO\(_3\)\(^{3-}\) or Ga(OH)\(_4\)\(^-\)

- Gallium (Ga) has an oxidation state of +3.

- Oxygen (O) has an oxidation state of -2.

- The formula for the gallate ion would be GaO\(_3\)\(^{3-}\) to balance the +3 charge on Ga with three -2 charges on O, resulting in a net -3 charge for the ion (3*(-2) + 3 = -3).

Option D: NaGa(OH)\(_4\) seems plausible because:

  1. Ga (+3) + 4OH (-1 each) → Ga(OH)\(_4\)\(^-\) (net charge -1)

  2. Na\(^+\) balances the charge, making NaGa(OH)\(_4\) a valid formula.

The most fitting formula for sodium gallate with gallium in the +3 oxidation state is option D, NaGa(OH)\(_4\).