问题如下：
If D.C company had a deferred tax asset of 1.6 million and a deferred tax liability of 1.4 million on its books in December 31, 20X7, but established a valuation allowance of 0.4 million in December 31, 20X8( all other things being equal). What was most likely happened during the 20X8?
选项：
A. It is likely that 0.4 million of the deferred tax liability's value will never be reserved.
B. It is likely that 0.4 million of the deferred tax asset's value will never be reserved.
C. It is likely that 0.4 million of the deferred tax asset's value will be a temporary difference.
解释：
B is correct.
It is likely that 0.4 million of the deferred tax asset's value will never be reserved, because of earning power is decrease and DTA is not be realized, so DTA will decrease by 0.4 million, its treated as valuation allowance.
能不能这样理解b项，在20*8年，0.4million的valuation allowance无法逆转？ 另外，valuation allowance和 dta长期看，是不是都可以逆转的？因为他们是此消彼长的关系，而且随着企业盈利与否变化？
