I don't understand why answer choice D is correct and not E?
I had a hard time trying to make an inference about the Concert of Europe reference from ln 14-17 because after I was done reading the line reference I couldn't look anywhere else in the passage that mentions the Concert of Europe. Since the 1st paragraph mentioned about multi-polar systems are a result of less powerful members grouping together to counter threats from larger groups, I thought this described the Concert of Europe which was why I choose E.
Thank you!