In an activity-based costing system, direct materials used would typically be classified as a unit-level cost batch-level cost product-sustaining cost facility-level cost Which of the following is not an example of a variable cost? straight-line depreciation on a machine with a 5 year useful life wages of assembly workers whose pay is based on hours worked tires used in the production of tractors aluminum used to make patio furniture At the break-even point, sales would be equal to contribution margin contribution margin would be equal to fixed expenses contribution margin would be equal to net operating income sales would be equal to fixed expenses Media Inc., an advertising agency, applies overhead to jobs based on direct professional labor hours. Overhead was estimated to be $150,000