$5$ points

A wheel rotating about a fixed axis has an angular position given by $=1\mathrm{.}0-2\mathrm{.}0t$ where $$ is measured in radians and $t$ in seconds. What is the angular acceleration of the wheel at $t=2\mathrm{.}0s?$

A$.0$

B$.1ra\frac{d}{s^2}$

C$.0\mathrm{.}5ra\frac{d}{s^2}$

D$.-2ra\frac{d}{s^2}$