YOKO, Inc. reports the following cost information for May: Cost of Goods Manufactured $75,000 Manufacturing Overhead 19,000 Finished Goods Inventory, May 1 5,000 Finished Goods Inventory, May 31 2,000 Work-in-Process Inventory, May 1 9,980 Work-in-Process Inventory, May 31 1,160 Direct Materials Used 25,400 What is the amount of direct labor incurred by YOKO in May? Select one: a. $6,400 b. None of the above c. $66,180 d. $21,780 e. $75,000