If 3 charges are placed at the vertices of equilateral triangle of charge ' $q$ ' each. What is the net potential energy, if the side of equilateral triangle is $\ell \mathrm{cm}$.
(A) $\left[1 /\left(4 \pi \epsilon_{0}\right)\right]\left(3 q^{2} / \ell\right)$
(B) $\left[1 /\left(4 \pi \epsilon_{0}\right)\right]\left(2 q^{2} / \ell\right)$
(C) $\left[1 /\left(4 \pi \epsilon_{0}\right)\right]\left(q^{2} / \ell\right)$
(D) $\left[1 /\left(4 \pi \epsilon_{0}\right)\right]\left(4 q^{2} / \ell\right)$