Maximize 10X1 + 7X2 + 5X3; subject to the constraints: X1 + X2 + X3 = 70; -X2 + X3

Maximize 10X1 + 7X2 + 5X3; subject to the constraints: X1 + X2 + X3 <= 100; 2X2 + X3 >= 70; -X2 + X3 <= 150. All variables are non-negative. Which of the following statements is true

The slack variable for -X2 + X3 <= 150 is zero.

The problem is infeasible.

The slack variable for X1 + X2 + X3 <= 100 is zero.

The slack variable for 2X2 + X3 >= 70 is positive.