In the diagram below $\Delta ABC$, where $AB=AC$, find $x$ </b> <br><br> <p>

Question

$\begin{array}{1 1} (a)\; 40^{\circ} \\ (b)\; 45^{\circ} \\ (c)\; 50^{\circ} \\ (d)\; 60^{\circ} \end{array}$