问题如下：
What is the least likely reason why ZP may need to change its accounting policies regarding inventory at some point after 2009?
选项：
A.The US SEC is likely to require companies to use the same inventory valuation method for all inventories.
B.The US SEC is likely to prohibit the use of one of the methods ZP currently uses for inventory valuation.
C.One of the inventory valuation methods used for US tax purposes may be repealed as an acceptable method.
解释：
A is correct.
The SEC does not require companies to use the same inventory valuation method for all inventories, so this is the least likely reason to change accounting policies regarding inventory. The SEC is currently evaluating whether all US companies should be required to adopt IFRS. If the SEC requires companies to adopt IFRS, the LIFO method of inventory valuation would no longer be allowed.
感觉这个题目不是判断最不可能的reason，而是判断ABC三个选项哪个场景是不可能存在的
