A simple harmonic oscillator has a period of 0.01 sec and an amplitude of 0.2 m. The magnitude of the velocity in ${\mathrm{msec}}^{-1}$  at the centre of oscillation is

• A

  $20\mathrm{\pi }$

• B

  100

• C

  $40\mathrm{\pi }$

• D

  $100\mathrm{\pi }$