GMATPrep5

Hey Rich,

Thanks for replying.I was fairly confused between A and C in this one. A says Oil prices crashed- which would that not have a similar effect?

Just wanted to know why not A.

While i don't think answer is A, I don't think it is still 'C' either. Because the statement says that new technology has made solar to electricity 'COST EFFICIENT'. Answer choice C states that EFFICIENCY of oil powered plants has increased. Is this Cost efficiency, transmission efficiency. We can assume that all efficiencies lead to cost efficiency.
Option E rather leads to very long assumption. Increased cost - promotes further exploration - increases supply - leads to price crash. Just like current oil prices. This may be another way of stating A.

A has a problem. Even though oil prices have fallen, we don't know whether other costs such as labour, materials etc have increased so that threshold remains high.

The choices are definitely narrowed down to A) and C). The problem arises in choosing which among st the two.
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Lets have a look at
A) The prices have fallen dramatically - For this to happen, means, that oil has become cheaper than it already was (it is cheaper than solar energy) - But none of the statements made in the argument point us towards the dropping price of oil.
C) Now, it becomes easier to choose C) via elimination. If one has eliminated A) the choice is obviously C). But if we think about it - The argument says the threshold economic viability between solar power and oil remains unchanged. This can mean the amount of energy generated by solar energy isn't useful enough even though cost of production/conversion has reduced. On the other hand, the word 'New' is a clue. 'New oil fired plants' which means these new ones are more efficient for some reason, one of them can be Technological Advances. So if one is confused about A). Thinking about C) this way can bring us closer to the answer as well
So, Answer is C.
I hope this helps.