pentagon corporation uses pressure pumps in the production of ro filters. the unit manufacturing costs for the pressure pumps are: line item description amount direct materials $12 direct labor 3 variable overhead 1 fixed overhead 5 pentagon uses 120,000 units of pressure pumps per year. hexagon corporation has offered to sell pentagon 120,000 units of pressure pumps per year for $17 each. fixed overhead is unavoidable. should pentagon manufacture the pressure pumps or buy them from hexagon corporation? a. pentagon should buy the pressure pumps because it will save $120,000. b. pentagon should make the pressure pumps because it will save $120,000. c. pentagon should buy the pressure pumps because it will save $480,000. d. pentagon should make the pressure pumps because it will save $480,000.