A uniform metal rod is used as a bar pendulum. If the room temperature rises by ${10}^0\mathrm{C},$and the coefficient of linear expansion of the metal of the rod is $2\times {10}^{-6}\mathrm{per}{}^0\mathrm{C},$ the period of the pendulum will have percentage increase of

• A

  $-2\times {10}^{-3}$

• B

  $-1\times {10}^{-3}$

• C

  $2\times {10}^{-3}$

• D

  $1\times {10}^{-3}$