When changing from the average cost method to FIFO, the company:

A. Records a journal entry to adjust the book balances from their current amounts to what those balances would have been using FIFO.
B. Revises comparative financial statements.
C. Includes in current year's income the cumulative after-tax difference that would have resulted if the company had used FIFO in all prior years.
D. All of these answer choices are correct.