A wire of mass m and length l is bent in the form of circular ring. The moment of inertia of the ring about its axis is

• A

  ml²

• B

  $\frac{{\mathrm{ml}}^2}{4{\mathrm{\pi }}^2}$

• C

  $\frac{{\mathrm{ml}}^2}{2{\mathrm{\pi }}^2}$

• D

  $\frac{{\mathrm{ml}}^2}{8{\mathrm{\pi }}^2}$