What Is the Optimal Solution (X, Y, Z) to the Following

Multiple Choice

What is the optimal solution (X, Y, Z) to the following linear program?
Max 2X + 4Y + 6Z
Subject to
Z ≤ 0
X + Y + Z ≤ 20
X, Y, Z ≥ 0

A) (0, 0, 20)
B) (20, 0, 0)
C) (0, 20, 0)
D) (20, 20, 20)
E) the solution is unbounded