Find the Maximum Value of the Objective Function and Where $\ge$

Find the maximum value of the objective function and where it occurs, subject to the constraints:
Objective function:

Z = 12x + 24y

Constraints:

X $\ge$ 0
Y $\ge$ 0
X + 4y $\le$ 20
X + y $\le$ 18
2x + 2y $\le$ 21

A) Maximum at (0, 5) : 120
B) Maximum at $\left( \frac { 22 } { 3 } , \frac { 19 } { 6 } \right)$ : 164
C) No maximum
D) Maximum at $\left( \frac { 21 } { 2 } , 0 \right)$ : 126
E) Maximum at (0, 0) : 0