Following are five series of costs A through E measured at various volume levels. Identify each series as either fixed, variable, mixed, step-wise, or curvilinear. Volume (Units) 0 400 800 1,200 1,600 2,000 2,400 Series A $ 8,800 8,800 8,800 8,800 8,800 8,800 8,800 Series B $ 0 5,120 10,240 15, 360 20,480 25,600 30,720 Series C $ 4,400 5,000 5,600 6,200 6,800 7,400 8,000 Series D S 7,900 8,690 9,480 10,797 12,640 17,775 Series E $4,800 4,800 5,800 5,800 6,800 6,800 7,800 Series A Series B Series C Series D Series E