单项选择题
At a time when 60 percent of the crude oil used by U.S. refineries comes from outside the countzy, President Bush says creating alternative sources of energy to replace fossil fuels is an economic and national security issue. In a series of recent speeches promoting his Advanced Energy Initiative, first unveiled at the State of the Union in January, Mr. Bush said it is time to address the world’s dwindling supply of fossil fuels.
What is the measure suggested by President Bush to deal with crude oil shortage?（）
A．Exporting crude oil coming from outside the country.
B．Creating alternative sources of energy to replace fossil fuels.
C．Promoting his 'Advanced Energy Initiative'.
D．Addressing the world's dwindling supply of fossil fuels.
