At which point is the following linear programming problem maximized

Maximize: $z=40x_{1}30x_2$

Subject to:

$x_1{x}_{2}12$

$2x_1{x}_{2}16$

$x_{1}0,x_{2}0$

$(4,8)$

$(18,01)$

$10,01$

$10,121$