Identify the costs as variable, fixed, or mixed. 1. Wood used in the production of furniture Variable 2. Fuel used in delivery trucks Variable . 3. Straight-line depreciation on factory building Fixed 4. Screws used in the production of furniture Variable 5. Sales staff salaries TFixed 6. Sales commissions Tvariable 7. Property taxes TFixed B. Insurance on buildings TFixed 9. Hourly wages of furniture craftsmen Variable 10. Salaries of factory supervisors Trixed 11. Utilities expense TMixed 12. Telephone bill Mixed