The number of values of $\alpha $ in $[0, 2\pi]$ for which $2\,{\sin ^3}\,\alpha  - 7\,{\sin ^2}\,\alpha  + 7\,\sin \,\alpha  = 2$ , is

  • [JEE MAIN 2014]
  • A

    $6$

  • B

    $4$

  • C

    $3$

  • D

    $1$

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