Identify the following costs: direct materials, direct labor or indirect costs for an automobile manufacturer. to. Oil used for assembly line machinery______________________ b. Salary of the plant manager ________________________ c. Salaries of workers who operate painting equipment______________________ d. Steel_______________________________ Identify the following costs: prime cost (P), conversion cost (C) or both (A) for a publishing company to. Glue used to bind books. ________________________ b. Maintenance of printing machines ________________________ c. Paper used to make a text___________________________ d. Salaries of printing machine workers __________________________