Thanks for asking this question.
For this one, we need to trace down to line 52 -57.
There, we have "Without a better understanding of the political implications of important variables such as..."then, you will find out variables "patterns of bilingualism," "rates of Mexican immigration," "naturalization," and "the variables in ethnic consciousness." However, be careful of the sentence since it hasn't finished yet.

Right after “ethnic consciousness” we have "these varibles help to create." That means other variables help to create "ethnic consciousness” which is exactly what Choice E says.
Hopefully, this make sense to you. If not, go back to those lines and double check the ideal they express.