[单项选择]Recently, the United Nations scientific panel studying climate change declared that the evidence of a warming trend is "unequivocal(清楚明白的)", and that human activity has "very likely" been the driving force in that change over the last 50 years. The last report by the group, the Intergovernmental Panel on Climate Change, in 2001, had found that humanity had "likely" played a role.
The addition of that single word "very" did more than reflect mounting scientific evidence that the release of carbon dioxide and other heat-trapping gases from smokestacks, tailpipes and burning forests has played a central role in raising the average surface temperature of the earth by more than 1 degree Fahrenheit since 1900. It also added new momentum(动力) to a debate that now seems centered less over whether humans are warming the planet, but instead over what to do about it. In recent months, business groups have banded together to make unprecedented(空前的) calls for federal regulation of greenhouse
A. The debate gets unprecedented support from business group.
B. The rising temperature accelerates its development.
C. It focuses whether humans caused global warming.
D. It is about what people should do to discontinue warming.