$A$ ring of radius $r$ and mass $m$ is rotating with an angular velocity $\omega$ about an axis passing through its center and perpendicular to its plane. Its kinetic energy will be:

• A
  $mr\omega^2$
• B
  $mr^2\omega^2/2$
• C
  $mr^2\omega^2$
• D
  $\frac{1}{2}mr^2\omega^2$