Solve the following linear program graphically. Maximize Z = (4X1 + 5X2); subject to the constraints: X1 + 2X2 <= 10; 6X1 + 6X2 <= 36; X1 <= 4; X1>= 0; X2 >= 0. Which of the following statements is true?
A. (0, 6) is a corner point of the feasible region.
B. The constraint 6X1 + 6X2 <= 36 has a slack of zero in the optimal solution
C. (6,0) is a corner point of the feasible region.
D. The optimal solution value is unbounded.