A thin uniform rod $($length $=1\mathrm{.}2$ m$,$ mass $=2\mathrm{.}0$ kg$)$ is pivoted about a horizontal, frictionless pin through one end of the rod. $($The moment of inertia of the rod about this axis is ML$2/3.)$ The rod is released when it makes an angle of $37$ with the horizontal. What is the angular acceleration of the rod at the instant it is released? I $=$ML$2/3$

$$

A$.$

$9\mathrm{.}8$ rad$/$s$2$

B$.$

$65$ rad$/$s$2$

C$.$

$0$

D$.$

$12$ rad$/$s$2$