a$.$ If I can only concentrate on getting the best forecasts of one variable, it should be Variable A because it has the largest negative slope. b$.$ If I expect up to $+25\%$ error may exist in my forecast for all of these variables, the acceptance of this project may be at risk. c$.$ Making sure I have a good estimate of Variable D is extremely important in planning this project. d$.$ Variable B is the sales revenue in this example.