Answer:
A change in accounting principle for which the financial statements for prior periods included for comparative purposes should be presented as previously reported.
Explanation:
Since the accounting method is being changed from FIFO to LIFO, any adjusting of prior year balances would be impractical. If the change is from LIFO to FIFO, then it makes more sense to adjust prior year balances. By impractical, it means that any changes would be too difficult and expensive to determine, and the value of the change is insignificant (materiality principle).
Generally US GAAP rules require that changes from FIFO to LIFO be disclosed in the footnotes only.