Cover-to-Cover Company is a manufacturer of shelving for books. The company has compiled the following cost data, and wants your help in determining the cost behavior. After reviewing the data, complete requirements (1) and (2) that follow. Units Produced Total Lumber Cost Total Utilities Cost Total Machine Depreciation Cost 9,000 shelves $108,000 $11,350 $130,000 18,000 shelves 216,000 21,700 130,000 36,000 shelves 432,000 42,400 130,000 45,000 shelves 540,000 52,750 130,000 1. Determine whether the costs in the table are variable, fixed, mixed, or none of these