This is an analogy question that is supposed to correspond with a specific section of text, lines 10-18. The first thing we do is locate those lines, give them a quick read through, and extract the important information. We are supposed to find a situation analogous to this historical trend. What is that trend?
The trend is that the global diversity (1) swiftly rose; (2) plateaued; and (3) slowly but steadily rose again. We want to find something that is analogous to this! So we look for "rise → plateau → steadily rise again"
(A) Decline → steadily rise. Eliminate.
(B) Fluctuates → stabilizes. Eliminate.
(C) Fluctuates. Eliminate.
(D) Rise → Levels off → steadily decrease. Eliminate, but close!
(E) Rise rapidly → Constant → Gradually rise. Perfect! (E) is correct!