Determine the total amount of manufacturing overhead from the cost information provided by the accountant: Direct materials $33,000, Depreciation on factory equipment $12,000, Factory janitor's salary $23,000, Direct labour $28,000, Utilities for factory $9,000, Selling expenses $16,000, Production supervisor's salary $34,000, Administrative expenses $21,000. Select one: O a. $78,000 O b. $139,000 O c. $37,000 O d. $44,000