Consider the following costs: Production supervisors salary 34,000 Direct materials 27,000 Selling expenses 16,000 Indirect materials 22,000 Depreciation of factory equipment 25,000 Direct labour 23,000 Utilities for factory 9,000 Administrative expenses 21,000 What is the total amount of manufacturing overhead? a. 90,000 b. 89,000 c. 140,000 d. 68,000