The diameter of a brass rod is 4 mm and Young's modulus of brass is  $9\times {10}^{10}\mathrm{N}/{\mathrm{m}}^2$. The force required to stretch by 0.1% of its length is

• A

  $360\mathrm{\pi N}$

• B

  $36 \mathrm{N}$

• C

  $144\mathrm{\pi }\times {10}^3\mathrm{N}$

• D

  $36\mathrm{\pi }\times {10}^5\mathrm{N}$