请教prep－16 无法排除选项

16.   (27621-!-item-!-188;#058&003223)

Most of the world's supply of uranium currently comes from mines.  It is possible to extract uranium from seawater, but the cost of doing so is greater than the price that uranium fetches on the world market.  Therefore, until the cost of extracting uranium from seawater can somehow be reduced, this method of obtaining uranium is unlikely to be commercially viable.

Which of the following would it be most useful to determine in evaluating the argument?

(A) Whether the uranium in deposits on land is rapidly being depleted

(B) Whether most uranium is used near where it is mined

(C) Whether there are any technological advances that show promise of reducing the cost of extracting uranium from seawater

(D) Whether the total amount of uranium in seawater is significantly greater than the total amount of uranium on land

(E) Whether uranium can be extracted from freshwater at a cost similar to the cost of extracting it from seawater

A和C我不知道该怎么做排除 我觉得都相关

望高人指点 谢谢大家

我知道A的话 如果陆地上的U都要用完 那么从海水提炼的成本就无关紧要了

C的话 如果技术可能降低成本 那么可能成本还是会很高 没有商业价值 但也可能会降低很多 使得商用的可能性增加

所以 我实在不知道怎么排除选项

请大家讨论

对A没感觉，如果我是改项目的决策者，我会选择C来完成项目。

....可是答案是A啊

希望大家帮忙说说想法

也许对解题思路有帮助