The value of ${\cos ^2}\,{10^o}\,\, - \,\cos \,\,{10^o}\,\cos \,\,{50^o}\, + \,{\cos ^2}\,{50^o}$ is

  • [JEE MAIN 2019]
  • A

    $\frac{3}{2}\,(1\, + \,\cos \,{20^o})$

  • B

    $\frac {3}{4}$

  • C

    $\frac {3}{2}$

  • D

    $\frac{3}{4}\,\, + \,\,\cos \,{20^o}$

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