GI Designs, a copper furniture manufacturer, increased the price on its copper tabletops by 20 percent for three months to see what the effect would be on its sales. The price increase is the in this three-month experiment.

The correct answer is letter "C": independent variable.

Explanation:

Independent variables are propositions in a study which effects help to analyze certain behavior of a dependent variable. The dependent variable does not change but the independent variables do. There may be more than one independent variable for only one dependent variable.

In the case, the dependent variable is the change in sales at GO designs while the independent variable is the price increase.

answer; engaging in effective public relations;

answer; organization;