A particle executes SHM with a time period of 16 s. At time t = 2s, the particle crosses the mean position while at t = 4s, its velocity is 4ms^–1. The amplitude of motion in metre is

• A

  $\sqrt{2}\mathrm{\pi }$

• B

  $16\sqrt{2}\mathrm{\pi }$

• C

  $32\sqrt{2}/\mathrm{\pi }$

• D

  $4/\mathrm{\pi }$