Identify the following items as fixed, variable, or mixed costs. wood for making a table salary of plant supervisor nails used in making a table wages of wood cutters straight-line depreciation on plant equipment legal fees paid at $20,000 plus $100 per hour over 100 hours insurance on inventory at $10,000 plus $3 for every $300 in inventory balance rental cost for storage space, $5,000 per month F a.fixed b.variable c. mixed