In the figure given below $PT$ and $PQ$ are targets to the circle with centre $o$. Which of the following is equal to $z^{\circ}$ ?

Question

$\begin{array}{1 1} (a)\; x^{\circ} \\ (b)\; 180^{\circ}-x \\ (c)\; x+w+y \\ (d)\; \text{none of the above} \end{array}$