Following are four series of costs measured at various volume levels. Identify each series as either fixed, variable, mixed, or step-wise Hint it can help to graph each cost series. Volume (Units) Series A Series B $ 1,840 e 400 see 1,200 1,60e 2.ee 2,480 $ 2,540 3,140 3,748 4,340 4,940 5,540 6,140 1,040 2,080 2,08 3, 120 3,120 4,160 Series C $ 5,040 5,840 5,840 5,840 5,840 5,040 Series D $ 3,640 7,280 10,92e 14,56e 18, 200 21,840 5,84e Series A Series B Series C Series D