(D) is correct because the first author uses the study as an example of the phenomenon of rivalry, which lines 24-28 make clear. Right after bringing up this phenomenon, the author cites the study. Passage B, on the other hand, introduces and refutes the Solnick and Hemingway study, and introduces it in its very first sentence.
(B) is wrong because the question asks about the authors of passage A and B respectively. But passage A uses the study as evidence,e and passage B presents it as a view to be argued against - the order in this answer choice is reversed. Hope this helps!