If power factor is 1/2 of a series RL  AC circuit, where $\mathrm{R}=100 \mathrm{\Omega } \mathrm{and} \mathrm{supply} \mathrm{frequency} \mathrm{is} 50 \mathrm{Hz}$ then L is

• A

  $\frac{\sqrt{3}}{\mathrm{\pi }}\text{ henry }$

• B

  $\mathrm{\pi }\text{ henry }$

• C

  $\frac{\mathrm{\pi }}{\sqrt{3}}\text{ henry }$

• D

  None of these