A particle of charge $q$ and mass $m$ is subjected to an electric field $E = E _{0}\left(1- ax ^{2}\right)$ in the $x-$direction, where $a$ and $E _{0}$ are constants. Initially the particle was at rest at $x=0 .$ Other than the initial position the kinetic energy of the particle becomes zero when the distance of the particle from the origin is

  • [JEE MAIN 2020]
  • A

    $\sqrt{\frac{2}{a}}$

  • B

    $\sqrt{\frac{1}{a}}$

  • C

    $a$

  • D

    $\sqrt{\frac{3}{a}}$

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