A uniform metal rod is used as a bar pendulum. If the room temperature rises by \[10{}^\circ C\], and the coefficient of linear expansion of the metal of the rod is \[2\times {{10}^{-\,6}}\text{per}\,{}^\circ C\], 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. \[1\times {{10}^{-\,3}}\]