Which types of overhead allocation methods result in the use of more than one overhead rate during the same time period? Select one: O a. Departmental overhead rate method and activity-based costing. O b. Departmental overhead rate method and cost pool overhead rate method. c. Cost pool overhead rate method and plantwide overhead rate method. d. Plantwide overhead rate method and departmental overhead rate method. O e. Activity-based costing and plantwide overhead rate method.