Reading Comprehension

It's beyond my understanding.. Can anyone explain?

This answer E comes down to the sentence: "...many European countries and the United States conquered high (by these countries' standards) inflation..."

The portion in parentheses qualifies the word "high." Were the sentence to not contain that parentheses portion, then E would not be correct. However, because the passage is specifying that it is high "by these countries' standards," then that would imply that it would not necessarily be considered high in other places. This leads nicely to answer choice E.

I hope this helps!!!