Help~GMATPrep上的一道语法题目，thanx!

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

A as varied as

B as varied as are

C as varied as those of

D that are as varied as

E that are varied as are

answer: A, why not D?

我觉得A差一个on,如果改成as varied as on就可以避免歧义了，如果不加on的话，就不知道是China...are having a positive effect on..还是green-taxes are having a positive effect on China...

D就解决了我所觉得的歧义问题that后面引导一个定语从句了，翻译为green-taxes are having a positive effect on 像China...一样varied的countries.

不知道我的理解哪里不对呢？

求指教~~

many thanx!

，which...，可以直接忽略，应该没有岐义

as及后面修饰countries，不是比较，刚读时也以为是比较，看看发现是说这个taxes对如此不同的国家，C,N,H都有好的影响

thanx!

then D is redundant for its use of that are?