Penny, Inc. employs a process costing system. Direct materials are added at the beginning of the process. Information about July's activities is as follows: On July 1: Beginning inventories Direct materials cost Conversion costs During July: Number of units started Direct materials added Conversion costs added On July 31: 850 units, 60% complete $5,000 $4,000 15,000 $155,000 $83,520 Ending inventories 1,600 units, 40% complete Using the FIFO method, the number of units started and completed in July was Oa. 14,250 Ob. 13,400 Oc. 15,740 Od. 15,000