To see why (E) is right, take a look at the referee to the Solnick and Hemingway study in lines 24-33, which supports the author's position using data. For passage B, take a look at line 50, in which the author cites "the data."
(D) is wrong because the word "paradox" is a bit too strong of a word to describe the situation. While relative prosperity seeming more important than absolute wealth may be unintuitive, it doesn't rise to the level of "paradoxical." Hope this helps!