Two charges q and – 3q are fixed on x-axis separated by distance d. Where should a third charge 2q be placed from A such that it will not experience any force?

• A

  $\frac{\mathrm{d}-\sqrt{3}\mathrm{d}}{2}$

• B

  $\frac{\mathrm{d}+\sqrt{3}\mathrm{d}}{2}$

• C

  $\frac{\mathrm{d}+3\mathrm{d}}{2}$

• D

  $\frac{\mathrm{d}-3\mathrm{d}}{2}$