阅读下列四篇短文，从每小题后所给的A,B,C或D四个选项中，选出最佳选项。
We already know the fastest, least expensive way to slow climate change: Use less energy. With a little effort, and not much money, most of us could reduce our energy diets by 25 percent or more—doing the Earth a favor while also helping our wallets.
