Find the Maximum Value of the Objective Function and Where

Multiple Choice

Find the maximum value of the objective function and where it occurs,subject to the indicated constraints. ​
Objective function:
​
Z = 9x + 5y
​
Constraints:
​
0 ≤ x ≤ 60
0 ≤ y ≤ 45
5x + 6y ≤ 420​ ​

A) Maximum at (0,45) : 225
B) Maximum at (0,0) : 0
C) Maximum at (30,45) : 495
D) Maximum at (60,20) : 640
E) Maximum at (60,0) : 540