Answer:
A. A only
Step-by-step explanation:
U.S. Generally Accepted Accounting Principles (GAAP) does not allow property, plant, and equipment to be written up or revalued. If the fair value of PP&E falls below the book value and the amount is material then a company must write down the asset to fair value.
Since under US GAAP, once PPE is written, it can not be reversed. as Company B is indicated to have reversed the write down while company A did not. It therefore means that Company A only is reporting under US GAAP.