Charges +q and -q are placed at points A and B respectively. Which are at a distance 2 L apart,C is the midpoint between A and B. The work done in moving a charge +Q along the semicircle CRD is :

• A

  $\frac{\mathrm{qQ}}{4{\mathrm{\pi \epsilon }}_0\mathrm{L}}$

• B

  $\frac{\mathrm{qQ}}{2{\mathrm{\pi \epsilon }}_0\mathrm{L}}$

• C

  $\frac{\mathrm{qQ}}{6{\mathrm{\pi \epsilon }}_0\mathrm{L}}$

• D

  $-\frac{\mathrm{qQ}}{6{\mathrm{\pi \epsilon }}_0\mathrm{L}}$