is no doubt that using energy efficiently reduces the release of greenhouse gases.A It B

问题补充：

is no doubt that using energy efficiently reduces the release of greenhouse gases.

A It B This C That D There

答案：

解析：考查句型：there is no doubt that毫无疑问做某事。句意：毫无疑问有效地使用能源会减少温室气体的释放。故选D。