(A) as varied as - Correct
(B) as varied as are
(C) as varied as those of
(D) that are as varied as
(E) that are varied as are

I am struck between A and D.

The comparison the sentence is trying to make is among countries.

In option A this is clear by use of 'as varied as'

In option D 'that' clearly modifies countries and conveys the same meaning as option A. But I think because of concision we need to pick A. I feel A is right. What is OA?

whhy is D wrong ?

consider the difference between these two sentences, which would illustrate the point:
(1) I get mail from cities as far away as Providence.
(2) I get mail from cities that are as far away as Providence.

If I'm in San Francisco, then sentence #2 means, strangely enough, that I get mail from cities that are all exactly 3,082 miles away (the distance from SF to Providence). Sentence #1 implies no such thing.

Similarly, the wrong answer (D) seems to imply that EACH country is somehow as 'varied' as EACH other country. That's not the intended meaning, which is that the SET of countries is varied.

any experts mitch hunt, Rich cohen and others like to try this one ???