[单项选择]Cars account for half the oil consumed in the US, about half the urban pollution and one-fourth the greenhouse gases. They take a similar oil of resources in other industrial nations and in the cities of the developing world. As vehicle use continues to increase in the coming decade, the US and other countries will have to deal with these issues or else face unacceptable economic, health-related and political costs. It is unlikely that oil prices will remain at their current low level or that other nations will accept a large and growing US contribution to global climatic change.
Policymakers and industry have four options: reduce vehicle use, increase the efficiency and reduce the emissions of conventional gasoline-powered vehicles, switch to less harmful fuels, or find less polluting driving systems. The last of these -- in particular the introduction of vehicles powered by electricity -- is ultimately the only sustainable option. The other alternatives are attractive in theor
A. The use of fuels other than gasoline.
B. Improved energy efficiency.
C. The introduction of less polluting driving systems.
D. Reducing car use by carpooling.

[单项选择]Cars account for half the oil consumed in the US, about half the urban pollution and one-fourth the greenhouse gases. They take a similar oil of resources in other industrial nations and in the cities of the developing world. As vehicle use continues to increase in the coming decade, the US and other countries will have to deal with these issues or else face unacceptable economic, health-related and political costs. It is unlikely that oil prices will remain at their current low level or that other nations will accept a large and growing US contribution to global climatic change.
Policymakers and industry have four options: reduce vehicle use, increase the efficiency and reduce the emissions of conventional gasoline-powered vehicles, switch to less harmful fuels, or find less polluting driving systems. The last of these — in particular the introduction of vehicles powered by electricity — is ultimately the only sustainable option. The other alternatives are attractive in theory
A. consume half of the oil produced in the world
B. have serious consequences for the well-being of all nations
C. widen the gap between the developed and developing countries
D. impose an intolerable economic burden on residents of large cities