Use Graphical Methods to Solve the Linear Programming Problem $z=4 x+5 y$

Multiple Choice

Use graphical methods to solve the linear programming problem.
-Minimize $z=4 x+5 y$
Subject to: $\quad 2 x-4 y \leq 10$
$2 x+y \geq 15$
$x \geq 0$
$y \geq 0$

A) Minimum of 33 when $x=7$ and $y=1$
B) Minimum of 39 when $x=1$ and $y=7$
C) Minimum of 20 when $x=5$ and $y=0$
D) Minimum of 75 when $x=0$ and $y=15$