The Young's modulus of the materials of the rod is,${\text{2×10}}^{11}N/m^2$ and its density is 8000 kg/m³. The time taken by a sound wave to traverse 1 m of the rod will be
 

• A

  ${10}^{-4}\mathrm{s}$

• B

  $2\times {10}^{-4}s$

• C

  $8\times {10}^{-2}\mathrm{s}$

• D

  $16\times {10}^{-2}\mathrm{s}$