The right answer is D.Meaning: Just as listening helps students understand the 1930s, so reading helps students grasp the post-Civil War era.
Two splits can help to solve this question.
Split #1: we are comparing the 1930s with something. Should be the post-Civil War era, the immense strife and challenge America faced?
Split#2: The right usage of the idiom just as X so Y.
Split #1: The 1930s is structurally parallel to the post-Civil War era. The 1930s is an era or period in the past and so was the post-Civil War era. Hence, it is logical to compare the 1930's with an era, being the post-Civil War era. Based on this, we can eliminate A.
Split#2: The right usage of the idiom is just as X so Y. X and Y must be parallel. Based on this, we can eliminate B and C. A can also be eliminated because listening is not parallel to Abraham Lincoln's.
Between D and E, D is better because there is a direct comparison between the 1930s and the post-Civil War era, with
a time of immense domestic challenge and strife as the non-essential modifier. The non-essential modifier, however, is what is given precedence in E and this is not right. We can eliminate E and keep D as the best answer.
Just as listening to Franklin D. Roosevelt's famous fireside chats helps students of history
understand the 1930s, an era marked by incredible domestic economic distress and unparalleled foreign conflict, so Abraham Lincoln's famous Second Inaugural Address helps students
grasp the immense strife and challenge America faced in the post-Civil War era.
(A)
so [
reading]Abraham Lincoln's famous Second Inaugural Address helps students
grasp the immense strife and challenge America faced in the post-Civil War era.
(B)
Abraham Lincoln's famous Second Inaugural Address helps students
grasp the post-Civil War era, a time of immense domestic challenge and strife.
(C)
reading Abraham Lincoln's famous Second Inaugural Address helps students
grasp the post-Civil War era, a time of immense domestic challenge and strife
(D)
so reading Abraham Lincoln's famous Second Inaugural Address helps students
grasp the post-Civil War era, a time of immense domestic challenge and strife
(E)
so reading Abraham Lincoln's famous Second Inaugural Address helps students
grasp a time of immense domestic challenge and strife--the post-Civil War era