A thin uniform rod of length `l` 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 -
A. `(1)/(3) (l^(2) omega^(2))/(g)`
B. `(1)/(6) (l omega)/(g)`
C. `(1)/(2) (l^(2) omega^(2))/(g)`
D. `(1)/(6) (l^(2) omega^(2))/(g)`
