Use the Two-Stage Method to Solve $x_{1} \geq 0$ And $x_{2} \geq 0$

Multiple Choice

Use the two-stage method to solve.
-Find $x_{1} \geq 0$ and $x_{2} \geq 0$ such that
$$\begin{aligned}& x_{1}+x_{2} \leq 25 \\& x_{1}+2 x_{2} \geq 15 \\& 2 x_{1}+x_{2} \leq 30\end{aligned}$$
And $\mathrm{z}=4 \mathrm{x}_{1}+2 \mathrm{x}_{2}$ is maximized.

A) $x_{1}=15, x_{2}=0, z=60$
B) $x_{1}=15, x_{2}=10, z=80$
C) $x_{1}=25, x_{2}=0, z=100$
D) $x_{2}=30, x_{1}=0, z=60$