Given circle $\underline{O}$ with radius $\overline{O T},$ tangent $\overline{A D},$ and line segments $\overline{O A}, \overline{O B}, \overline{O C}$
and $\overline{O D}$:
a) Which line segment drawn from $O$ has the
smallest length?
b) If $m \angle 1=40^{\circ}, m \angle 2=50^{\circ}, m \angle 3=45^{\circ},$ and
$\mathrm{m} \angle 4=30^{\circ},$ which line segment from point $O$ has the greatest length?
(FIGURE CANNOT COPY)