Family furniture corporation incurred the following costs. identify the costs as variable, fixed, or mixed. 1. wood used in the production of furniture. select a type of costs 2. fuel used in delivery trucks. select a type of costs 3. straight-line depreciation on factory building. select a type of costs 4. screws used in the production of furniture. select a type of costs 5. sales staff salaries. select a type of costs 6. sales commissions. select a type of costs 7. property taxes. select a type of costs 8. insurance on buildings. select a type of costs 9. hourly wages of furniture craftsmen. select a type of costs 10. salaries of factory supervisors. select a type of costs 11. utilities expense. select a type of costs 12. telephone bill. select a type of costs