(c)
${Sn}^{2 +}$ → ${Sn}^{4 +}$ + ${2e}^{-}$
$E_{cell}$ = $E^{{^\circ}}$ - $\frac{0.059}{n}\log\frac{\left\lbrack {Sn}^{4 +} \right\rbrack}{\left\lbrack {Sn}^{2 +} \right\rbrack}$
= $E^{{^\circ}}$ - $\frac{0.059}{2}\log\left\lbrack \frac{0.01}{0.1} \right\rbrack$
= $E^{{^\circ}}$ + $\frac{0.059}{2}$