Direct Disk Drive Company operates a computer disk manufacturing plant. Direct materials are added at the end of the process. The following data were for August 2017:

Work in process, beginning inventory 151,400 units

Transferred-in costs (100% complete)

Direct materials (0% complete)

Conversion costs (80% complete)

Transferred in during current period 451,200 units

Completed and transferred out 400,600 units

Work in process, ending inventory 202,000 units

Transferred-in costs (100% complete)

Direct materials (0% complete)

Conversion costs (55% complete)

Calculate equivalent units for conversion costs using the FIFO method.

a. 30,280 units b. 353,400 units c. 299,800 units d. 390,580 units