A particle executes SHM along a straight line 4cm long. When the displacement is 1cm its velocity and acceleration are numerically equal. The time period of SHM is

• A

  $2\mathrm{\pi s}$

• B

  $\frac{2\mathrm{\pi }}{\sqrt{3}}\mathrm{s}$

• C

  $\frac{2\mathrm{\pi }}{\sqrt{5}}\mathrm{s}$

• D

  $\frac{2\mathrm{\pi }}{\sqrt{7}}\mathrm{s}$