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. go Volume (Units) 0 400 800 1,200 1,600 2,000 2,400 Series A $ 4,600 4,600 5,600 5,600 6,600 6,600 7,600 Series B $ 8,600 8,600 8,600 8,600 8,600 8,600 8,600 Series C $ 0 5,040 10,080 15,120 20,160 25, 200 30, 240 Series D $4,300 4,900 5,500 6,100 6,700 7,300 7,900 Series E $ 7,800 8,580 9,360 10,660 12,480 17,550 Series A Series B Series C Series D Series E