求解 PREP

82.   (33511-!-item-!-188;#058&007598)

Technological improvements and reducedequipment costs have made converting solar energy directly into electricity farmore 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 solarpower plants to be more economical than new oil-fired power plants) isunchanged at thirty-five dollars.

Which of the following, if true, doesmost to help explain why the increased cost-efficiency of solar power has notdecreased its threshold of economic viability?

A. The cost of oil has fallendramatically.

B. The reduction in the cost ofsolar-power equipment has occurred despite increased raw material costs forthat equipment.

C. Technological changes have increasedthe efficiency of oil-fired power plants.

D. Most electricity is generated bycoal-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.