Six charges are placed at the vertices of a regular hexagon as shown in the figure. The electric field on the line passing through point O and perpendicular to the plane of the figure as a function of distance x from point O is (assume x >>a)

• A

  0

• B

  $\frac{\mathrm{Qa}}{{\mathrm{\pi \epsilon }}_0{\mathrm{x}}^3}$

• C

  $\frac{2\mathrm{Qa}}{{\mathrm{\pi \epsilon }}_0{\mathrm{x}}^3}$

• D

  $\frac{\sqrt{3}\mathrm{Qa}}{{\mathrm{\pi \epsilon }}_0{\mathrm{x}}^3}$