saved Help Save & Eal Listed here are four series of separate costs measured at varlous volume levels. Volume (Unite) Series 1 Series 2 Series 3 Series 4 0 450 800 $ 100 105 100 800 450 800 200 1,600 450 800 1,600 120 145 190 250 300 400 2,400 450 3,200 4,000 4,800 450 1,600 2,400 2,400 500 450 450 600 320 Examine each series and identify whether it is best described as a fixed, variable, step-wise, or curvillinear cost. (t can help to graph the cost series.) Series 1 Series 2 Series 3 Series 4