Suppose that in an optimization problem, the objective function is given by u(X₁, X₂) = 10 +2X₁ + 4X₂ . Suppose that there are two optimal solutions,and that one of them is (X₁, X₂) = (1, 2). What must be the value of the objective function at the other optimal solution?

a. It cannot possibly be determined without knowledge of what the constraints are.

b. 20.

c. 10.

d. Even if we knew what the constraints are, we'd need to know the actual numbers themselves to determine the answer.