单选题 How much of American GNP comes from sectors that are affected by climate change ?

A、 3%.
B、 10%.
C、 87%.
D、 13%.

【正确答案】 D

【答案解析】[分析] 细节题，计算题。参见原文：About 3% of American GNP originates in climate-sensitive sectors such as farming and forestry．Another 10% comes from sectors only modestly sensitive-energy，water system property and construction．