A thick straight wire of length $\mathrm{\pi }$m is fixed at its midpoint and then bent in the form of a circle. The shift in its centre of mass is

• A

  $\mathrm{\pi m}$

• B

  0.5 m

• C

  2 m

• D

  $\frac{\mathrm{\pi }}{2}\mathrm{m}$