The magnetic susceptibility of a material of a rod is $499$. The absolute permeability of vacuum is$4\pi \times {10}^{-7} \mathrm{H }{\mathrm{m}}^{-1}$. The absolute permeability of the material of a rod is

• A

  $\pi \times {10}^{-4} \mathrm{H }{\mathrm{m}}^{-1}$
• Correct answer
  B

  $2\pi \times {10}^{-4} \mathrm{H }{\mathrm{m}}^{-1}$
• C

  $3\pi \times {10}^{-4} \mathrm{H }{\mathrm{m}}^{-1}$
• D

  $4\pi \times {10}^{-4} \mathrm{H }{\mathrm{m}}^{-1}$

Hence, the correct answer is option: 'B'.