CR - uranium

I eliminate B, D & E from the possible answers so keep A and C.

I go for C, link between technology and cost

A is incomplete for me, there might be another technique than mining or seawater extraction.

Would like to know the answer

A.

what is the source of this question?

I am confused between A) and C) since both look irrelevant.
May be C) is more relevant since for A) there is a possibility of having another source of uranium apart from mines and seawater.

OA: A
Source: GMATPrep

GMATPrep Exam 1 Verbal #36 (for me)

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

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

Correct answer is (a).

I answered (c) though because I saw that direct link between costs. I would think that the bolded part above would direct lend itself to answer (c). I can see how (a) is possible but (a) seems to already be understood. Why would they be investigating the seawater method unless it was being depleted. Also, commercial viability seems to want a link to costs, and not the amount of remaining resources.

It's between C and D, but I will go for C.

Conclusion: Until the price of extracting Uranium from Sea water falls this method will not be comercially viable

Premise: most of the world's Uranium is extracted from mines but it can also be extracted from sea water.

Hidden assumption: This method could be a viable method if costs can be reduced.

Therefore what will be most useful to determine in evaluating the argument will be whether or not there will be any advances in technology that show promise of reducing the price of uranium extracted from sea water.

It talks about costs not the amount available. In my opinion therefore D is out of scope.

I also fell in the C-trap. And when review it, I found that C definitely irrelevant because C says about technology, not directly about the cost of...But I can not persuade myselft that A. Can somebody help me to figure out A in a more detail?

I think it is hinged on the definition of commercial viability. It seems implicit that there is a need for uranium in the world so if there is none left on land, people would be willing to pay the additional cost for the more expensive seawater uranium. Hence, making it "commercially viable." If we were to really over-think it, we would also analyze whether this more expensive input would now make the consumers of it unprofitable. In this case, it would not be commercially viable, in my opinion.

But once again, I think I've just overanalyzed it to the point beyond the GMAT.

A

i think it is D

but what is the right ans pls send ?

Official Answer is A

A