A thin uniform rod of length $\ell$ and mass $m$ is swinging freely about a horizontal axis passing through its end. Its maximum angular speed is $\omega$. Its centre of mass rises to a maximum height of

Question

( A ) $\frac{1}{3} \frac{\ell^2 \omega^2}{g}$
( B ) $\frac{1}{6} \frac{\ell^2 \omega^2}{g}$
( C ) $\frac{1}{2} \frac{\ell^2 \omega^2}{g}$
( D ) $\frac{1}{6} \frac{\ell \omega}{g}$