Explanation

(d)
$\mathbf{\ KO}_{\mathbf{3}}$ $\mathbf{Na}_{\mathbf{2}}\mathbf{O}_{\mathbf{2}}$
Suppose O.N. of O = $x$ suppose
O.N. of O = $x$
$+ 1 + 3x = 0$ $2 \times 1 + 2x = 0$
$3x = \ - 1$ $2 + 2x = \ 0\ \ \ \ \ \ \$
$x = - \frac{1}{3}$ $2x = - 2$
$x = - 0.33$ $x = - \frac{2}{2}$
$x = \ - 1$