Three charges are placed at the vertices of an equilateral triangle of side 'a' as shown in the following Fig. The force experienced by the charge placed at the vertex A in a direction normal to BC is :

• A

  $\frac{{\mathrm{Q}}^2}{4{\mathrm{\pi e}}_0{\mathrm{a}}^2}$

• B

  $\frac{-{\mathrm{Q}}^2}{4{\mathrm{\pi e}}_0{\mathrm{a}}^2}$

• C

  Zero

• D

  $\frac{{\mathrm{Q}}^2}{2{\mathrm{\pi e}}_0{\mathrm{a}}^2}$