The number of elements in the set $S =\left\{\theta \in[0,2 \pi]: 3 \cos ^4 \theta-5 \cos ^2 \theta-2 \sin ^2 \theta+2=0\right\}$ is $...........$.

  • [JEE MAIN 2023]
  • A

    $10$

  • B

    $8$

  • C

    $9$

  • D

    $12$

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  • [JEE MAIN 2022]