What does Professor David Reay think of the use of microwaves?

A. It will become less popular in the coming decades.
B. It makes everyday cooking much more convenient.
C. It plays a positive role in environmental protection.
D. It consumes more power than conventional cooking. Reay,the use of microwaves 【定位】最后一段是David的观点Among common kitchen appliances used for cooking, microwaves are the most energy efficient, followed by a stove and finally a standard oven. Thus, rising microwave sales could be seen as a positive thing. 【同义替换】微波炉是最节能的;销量的上升是一件好事。和选项C的positive role in environment protection可以匹配。