Note: This Problem Requires the Use of a Linear Programming $$x _ { j } = \left\{ \begin{array} { l } 1 , \text { if location } j \text { is selected } \\0 , \text { otherwise }\end{array} \right.$$

Note: This problem requires the use of a linear programming application such as Solver or Analytic Solver.
A firm has prepared the following binary integer program to evaluate a number of potential locations for new warehouses. The firm's goal is to maximize the net present value of their decision while not spending more than their currently available capital.
Max 20x1 + 30x2 + 10x3 + 15x4
s.t. 5x1 + 7x2 + 12x3 + 11x4 ? 21 {Constraint 1}
X1 + x2 + x3 + x4 ? 2 {Constraint 2}
X1 + x2 ? 1 {Constraint 3}
X1 + x3 ? 1 {Constraint 4}
X2 = x4 {Constraint 5} $$x _ { j } = \left\{ \begin{array} { l } 1 , \text { if location } j \text { is selected } \\0 , \text { otherwise }\end{array} \right.$$
Set up the problem in Excel and find the optimal solution. What is the expected net present value of the optimal solution?

A) 20
B) 30
C) 35
D) 40
E) 45