Determine the total power dissipated through the circuit shown above in terms of $V, R_{t}, R_{z},$ and $R_{3}$ .
(A) $\frac{V^{2}}{R_{1}+R_{2}+R_{3}}$
(B) $\frac{R_{1}+R_{2}+R_{3}}{V^{2}}$
(C) $\frac{R_{1}\left(R_{2}+R_{3}\right)}{V^{2}\left(R_{1}+R_{2}+R_{3}\right)}$
(D) $\frac{V^{2}\left(R_{1}+R_{2}+R_{3}\right)}{R_{1}\left(R_{2}+R_{3}\right)}$