Martin Enterprises Inventories: April 1 April 30 Raw material $20,000 $17,000 Work in process 12,000 8,000 Finished goods 30,000 39,000 Additional information for April: Raw material purchased Direct labor payroll Direct labor rate per hour $45,000 $36,000 $8.00 Overhead rate per direct labor hour $10.00 Refer to Martin Enterprises. For April, conversion cost incurred was Select one: a. $81,000. b. $84,000. c. $36,000 d. $45,000