(d) Angle turned by the body
$\theta = \theta_{0} + \theta_{1}t + \theta_{2}t^{2}$
Angular velocity $\omega = \frac{d\theta}{dt}$
$= \frac{d}{dt}(\theta_{0} + \theta_{1}t + \theta_{2}t)$
$= \theta_{1} + 2\theta_{2}t$
Angular acceleration $\alpha = \frac{d\omega}{dt}$
$= \frac{d}{dt}\left( \theta_{1} + 2\theta_{2}t \right)$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = 2\theta_{2}$