\textbf{129-} In the figure, $O$ is the orthocenter of triangle $ABC$. The angle $A\hat{O}D$ equals which of the following?
\textit{[Figure: Triangle ABC inscribed in a circle, with O as orthocenter and D a point on the circle]}
\medskip
\hfill $O\hat{B}C\ (1$ \hfill $C\hat{A}D\ (2$ \hfill $O\hat{A}C\ (3$ \hfill $A\hat{D}O\ (4$
\bigskip
\hrule
\begin{center}
\textbf{Workspace}
\end{center}
%% Page 23