Material Is Added at the Beginning of a Process in a Process

Material is added at the beginning of a process in a process costing system.The beginning Work in Process Inventory for the process was 30 percent complete as to conversion costs.Using the FIFO method of costing,the number of equivalent units of material for the process during this period is equal to the

A) beginning inventory this period for the process.
B) units started and completed this period in the process.
C) units started this period in the process plus the beginning Work in Process Inventory.
D) units started and completed this period plus the units in ending Work in Process Inventory.