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

• A

  ${\mathrm{Q}}^2/\left(4{\mathrm{\pi \epsilon }}_0{\mathrm{a}}^2\right)$

• B

  $-{\mathrm{Q}}^2/\left(4{\mathrm{\pi \epsilon }}_0{\mathrm{a}}^2\right)$

• C

  Zero

• D

  ${\mathrm{Q}}^2/\left(2{\mathrm{\pi \epsilon }}_0{\mathrm{a}}^2\right)$