If $\alpha , \beta \, and \, \gamma$ are real numbers , then $D = \left|{\begin{array}{*{20}{c}}1&{\cos \,(\beta \, - \,\alpha )}&{\cos \,(\gamma \, - \,\alpha )}\\{\cos \,(\alpha \, - \,\beta )}&1&{\cos \,(\gamma \, - \,\beta )}\\{\cos \,(\alpha \, - \,\gamma )}&{\cos \,(\beta \, - \,\gamma )}&1 \end{array}} \right|$ =

  • A

    $-1$

  • B

    $\cos\, \alpha \, \cos \, \beta\, \cos \, \gamma$

  • C

    $\cos \, \alpha + \cos \, \beta + \cos \, \gamma$

  • D

    $0$

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