大全-17-14请帮忙看一下

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.

答案为C, 对此题有点晕, 请朋友们帮忙分析一下!!

为什么A不是呢?

Hereby, I just clears the threshold:

other costs of oil-fired power plant+ (current price of oil per barrel + 35 dollar)= current cost of the solar power plant;

Under the development and breakthrough of technology, cost of solar power plant has been declined, while the gap of 35 dollar remains stable. As a result, the reasonable explanation is costs of oil-fired power plant has been decreased as B claims