Which of the following is an assumption under FIFO processcosting method?

A.It assumes some of the highercost units are placed in ending work in process.

B.It assumes that all the lowercost units from the previous period in beginning work in process are the first to be completed and transferred out of the process.

C.It assumes that unit inputs costs are constant and do not fluctuate in the short run.

D.It assumes that the ending work in process consists of only the lowercost currentperiod units.