紧急请教GMAT语法题

So-called green taxes, which exact a price for the use of polluting or renewable fuels, are having a positive effect on the environment and natural resources base of countries as varied as China, the Netherlands, and Hungary. 

A. as varied as

B. as varied as those of

C. that are as varied as

D. as varied as are

E. that are varied as are

答案说A对，我觉得B对，请高人指点我一下，谢谢

划线部分前面已经有countries了，所以肯定是A