a) Direct materials include 0 only raw materials such as steel and glass O only major materials and components O all materials and components Direct labor includes only hourly production workers (aka assembly workers) O all production labor including supervisors and maintenance staff only managers who directly supervise the production process Manufacturing overhead includes O only non-manufacturing costs O only big items that cannot be traced (e.g., factory rent) O both big items that cannot be traced (e.g., factory rent) and small items that are not worth tracing (e.g., glue, grease) 0 only small items that are not worth tracing (e.g., glue, grease) b) Classify the following items as direct materials (DM), direct labor (DL), or manufacturing overhead (OH) for a car assembly plant: Rent for the factory building Cost of engines used in productionODL ODM OOH Depreciation on production equipment ODL ODM OOH Cost of lubricant used in productionODL ODM OOH Production supervisor's salary Assembly workers' wages ODL ODM OOH ODLDM OOH