The importance of for integer linear programming problems is often intensified by the fact that a small change in one of the coefficients in the constraints can cause a relatively large change in the value of the optimal solution.

The correct word to fill the blank will be "sensitivity analysis"

Explanation:

The sensitivity analysis is the study of how uncertainty in the output of a mathematical model affects an independent variable under certain given conditions or assumptions and how this contributes to the model's overall uncertainty.

b) to encourage free trade

c: in the east might be the correct answer