What are the three different inventory cost flowassumptions commonly used in com

What are the three different inventory cost flowassumptions commonly used in commerce today and allowed bygenerally accepted accounting principles? How does a companydetermine what cost flow assumption they should use? How does firstin first out cost flow assumption work? When it is mostappropriate to use? How does last in first out cost flowassumption work? When it is most appropriate to use? How does anaverage cost flow assumption work? When it is most appropriate touse?