The transfer function of a phase lead compensator is given by

$$D(s) = \frac{3 \bigg( s+ \frac{1}{3T} \bigg)}{ \bigg( s+ \frac{1}{T} \bigg)}$$

The frequency (in rad/sec), at which $\angle D(j \omega)$ is maximum, is

- $\sqrt{\frac{3}{T^2}}$
- $\sqrt{\frac{1}{3T^2}}$
- $\sqrt{3T}$
- $\sqrt{3T^2}$