A force of 6.4 N stretches a vertical spring by 0. I m. The mass that must be suspended from the spring so that it oscillates with a time period of $\frac{\mathrm{\pi }}{4}$ second.

• A

  $\frac{\mathrm{\pi }}{4}\mathrm{kg}$

• B

  $\frac{4}{\mathrm{\pi }}\mathrm{kg}$

• C

  1 kg

• D

  10 kg