c
Before
$\mathrm{V}_{\text {outer }}=\frac{\mathrm{kQ}}{2 \mathrm{R}}$
$\mathrm{V}_{\text {inner }}=\frac{\mathrm{k} \mathrm{Q}}{\mathrm{R}}$
$\mathrm{V}_{\text {inner }}-\mathrm{V}_{\text {outer }}=\frac{\mathrm{kQ}}{2 \mathrm{R}}=\mathrm{V}$
After
$\mathrm{V}_{\text {inner }}=\mathrm{V}_{\text {outer }}=\frac{\mathrm{k} Q}{2 \mathrm{R}}=\mathrm{V}$
