Which of the Following Is/are True

Which of the following is/are true?

A) Under U.S.GAAP, firms must test property, plant, and equipment for possible asset impairment when conditions indicate that a significant decrease in fair value has occurred.
B) Under U.S.GAAP, firms initially compare the undiscounted cash flows expected from the asset to the asset's carrying value.
C) Under U.S.GAAP, a fixed asset impairment occurs when the asset's carrying value exceeds the undiscounted cash flows.
D) Under U.S.GAAP, the amount of the recognized impairment loss is the excess of the carrying value over the fair value of the asset.
E) all of the above