Two equal charges $q$ are placed at a distance of $2a$ and a third charge $ - 2q$ is placed at the midpoint. The potential energy of the system is

  • A

    $\frac{{{q^2}}}{{8\pi {\varepsilon _0}a}}$

  • B

    $\frac{{6{q^2}}}{{8\pi {\varepsilon _0}a}}$

  • C

    $ - \frac{{7{q^2}}}{{8\pi {\varepsilon _0}a}}$

  • D

    $\frac{{9{q^2}}}{{8\pi {\varepsilon _0}a}}$

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