Which quotation from the speech most effectively develops the central idea that the south cared more about self-preservation than about the good of the nation as a whole?
a.)”each looked for an easier triumph, and a result less fundamental and astounding.”
b.) “while the inaurgural address was being delivererd from this place, devoted altogether to saving the union without ”
c.)”to strengthen, perpetuate, and extend this interest was the object for which the insurgents would rend the union even ”
d.)”with high hope for the future, no prediction in regard to it is ventured.”

C). ”To strengthen, perpetuate, and extend this interest was the object for which the insurgents would rend the Union even by,...”

Explanation:

As per the question, option C displays the quotation from the second inaugural address of Lincoln that most constructively advances the central idea i.e. 'south providing significance to self-preservation than the benefit of the nation as whole' which Lincoln felt was the key cause of the war. He said that they possessed an unusual yet powerful interest and in order to perpetuate, strengthen, and expand it, they tend to rupture the union 'even by war' while Lincoln desired the opposite(protect the union without having a war). Thus, option C is the correct answer.

your answer is b. "with strong wording encouraging readers to take action."