What is Chu's central idea regarding the United States'
role in the global clean energy race?
A. The U.S. is no longer an innovator of clean energy technologies.
B. The U.S. should work harder to compete in the development of clean energy technologies.
C. The U.S. missed the explosion in the solar technology market.
D. The U.S. must develop the capability to manufacture the energy products it invents.