[求助]2003年官方样题一道,NO.73,此题在2000年的官方样题中也出现,但答案不同，真正

73. In 1999, Baxter Company owned machinery that became permanently impaired. As of
December 31, 1999, the machinery had a book value of $800,000 and a market value of
$100,000. Baxter also owned a warehouse, located adjacent to a newly-opened transportation
hub. As of December 31, 1999, the book value of the warehouse was $1,200,000 and its
market value was $2,500,000. Baxter:
A. must recognize the loss on the machinery and the gain on the warehouse in 1999.
B. may recognize the loss on the machinery and the gain on the warehouse in 1999 or in later
years.
C. must recognize the loss on the machinery in 1999, but may not recognize the gain on the
warehouse until it is sold.
D. may recognize the loss on the machinery in 1999 or in later years, but may not recognize
the gain on the warehouse until it is sold.

在2003年给的答案是C

而在2000年给的答案却为D

请问到底哪一个答案才是正确的?

因为按照NOTES上的讲解 Managers have considerable discretion about the timing and amount of impairment recognition for assets the company intends to keep. 但同时书上也提到　Impairment must be recognized when the carrying value of an asset is higher than the sum of the future undiscouted CFs. Loss from the impairment of assets must be recognized when there is evidence of a lack of recoverability of the carrying amount.

所以我到底应该根据哪个理论来选择吗？到底是Ｃ还是Ｄ？到底是may recognized还是must be recognized？请高人帮帮忙！谢谢了！