Demographic studies show that Hispanics in the United States have esta

The right answer here is A. I see that both in the comments and in the 'selected answers' that a lot of aspirants have struggled with answer option D. So let's try an alternative approach, one that focus on parallelism and syntax to help us arrive at the right answer.

Options D & E - The demographic studies show us two separate and contradictory clauses. Hence, the right construction should be "Studies show us that xyz but that pqr". Options D and E are missing 'that', making them incorrect on parallelism grounds. OUT

Option C - The correct parallel construction should be "Hispanics have established blablabla.... they have been blablabla". The change in tense in C does not reflect this. OUT

Option B - This is more a matter of idiomatic usage. The construction "adjective + enough + that" is simply incorrect, and should instead be "so + adjective + that". Because of this, B is OUT, leaving us with the CORRECT answer A.

One thing to note: There are often going to be multiple reason to eliminate an option, and multiple approaches to order of elimination as well. You need NOT find every reason to eliminate an option, one will suffice. You also need not eliminate the answers in order. The GMAT doesn't care how you reached the right answer so long as you actually do.

- Matoo

Demographic studies show that Hispanics ..... but that they....
In D "that" is missing for it to be parallel.