$A$ charge $(-q)$ and another charge $(+Q)$ are kept at two points $A$ and $B$ respectively. Keeping the charge $(+Q)$ fixed at $B$,the charge $(-q)$ at $A$ is moved to another point $C$ such that $ABC$ forms an equilateral triangle of side $l$. The net work done in moving the charge $(-q)$ is

• A
  $\frac{1}{4\pi \varepsilon_0} \frac{Qq}{l}$
• B
  $\frac{1}{4\pi \varepsilon_0} \frac{Qq}{l^2}$
• C
  $\frac{1}{4\pi \varepsilon_0} Qql$
• D
  Zero