9. Management decides that all overhead costs only have three cost drivers: Direct labor hours Machine hours Number of purchase orders All overhead costs are then allocated to one of the activity cost pools. The table below lists all overhead costs: General Ledger Payroll taxes Machine maintenance Purchasing Dept. labor Fringe benefits Purchasing Dept. Supplies Equipment depreciation Electricity Unemployment insurance $1,000 $500 $4,000 $2,000 $250 $750 $1,250 $1,500 Which overhead costs do you think are driven by direct labor hours? Which overhead costs are driven by machine hours? And finally, which overhead costs are driven by # of purchase orders