What is the difference between a service firm and a manufacturer? A. a service firms largest cost of a job is labor where as a typical manufacturer direct labor is not the largest component but only part of the total cost of a job. B. the cost of a job for a service firm consists of direct labor and indirect costs and a cost of a job for a manufacturer consists of direct materials, direct labor and manufacturing overhead C. service firms allocate indirect period costs and a manufacturer allocates manufacturing overhead D. All of the above are differences between a service firm and a manufacturer