Fig. shows two parallel equipotential surfaces A and .B kept at a small distance r from each other. A point charge of - q coulomb is taken from the surface A to B. The amount of net work W done will be given by

• A

  $\mathrm{W}=-\frac{1}{4{\mathrm{\pi \epsilon }}_0}\left(\frac{\mathrm{q}}{\mathrm{r}}\right)$

• B

  $\mathrm{W}=\frac{1}{4{\mathrm{\pi \epsilon }}_0}\left(\frac{\mathrm{q}}{{\mathrm{r}}^2}\right)$

• C

  $\mathrm{W}=-\frac{1}{4{\mathrm{\pi \epsilon }}_0}\left(\frac{\mathrm{q}}{{\mathrm{r}}^2}\right)$

• D

  zero