Below are 5 sets of costs for Comany A - Company E in manufacturing different products measured at various volume levels. Analyze each set and select which is a) fixed, b) variable, c) mixed, d) step-wise, e) or curvlinear. Volume (Units) Series A Series B Series C Series D Series E 0 $ 5,000 $ 1,000 $ 0 $ 2,500 $ 0 400 5,000 1,000 6,000 3,100 3,600 800 5,000 2,000 6,600 3,700 7,200 1,200 5,000 2,000 7,200 4,300 10,800 1,600 5,000 3,000 8,200 4,900 14,400 2,000 5,000 3,000 9,600 5,500 18,000 2,400 5,000 4,000 13,500 6,100 21,600