被题目弄的有点晕,看不大懂.希望大家都读读,做做

14.   Technological improvements and reduced equipment costs have made converting solar energy directly into electricity far more cost-efficient in the last decade. However, the threshold of economic viability for solar power (that is, the price per barrel to which oil would have to rise in order for new solar power plants to be more economical than new oil-fired power plants) is unchanged at thirty-five dollars.

Which of the following, if true, does most to help explain why the increased cost-efficiency of solar power has not decreased its threshold of economic viability?

(A) The cost of oil has fallen dramatically.

(B) The reduction in the cost of solar-power equipment has occurred despite increased raw material costs for that equipment.

(C) Technological changes have increased the efficiency of oil-fired power plants.

(D) Most electricity is generated by coal-fired or nuclear, rather than oil-fired, power plants.

(E) When the price of oil increases, reserves of oil not previously worth exploiting become economically viable.

(that is, the price per barrel to which oil would have to rise in order for new solar power plants to be more economical than new oil-fired power plants) 此部分我知道是做题关键,可是怎么也和上面的the threshold of economic viability for solar power 连不起来呢.

希望看到的人把你们做的思路也一写吧,

谢谢了!!答案为C