Identify each cost below as variable, fixed, or mixed, relative to units sold. Explain your reason. Units Sold 25 50 75 100 Total Phone Cost $350 400 450 500 Materials cost per unit $120 120 120 120 Manager's salary $4,000 4,000 4,000 4,000 Depreciation cost per unit $70 40 30 25 Total utility cost $400 650 900 1,150 Total cost of goods sold $3,375 6,750 10,125 13,500 Units Sold Cost Type Reasoning Total Phone Cost Materials cost per unit Total cost of goods sold Total utility cost Depreciation cost per unit Manager's salary