I chose C as the correct answer and my thought process in reaching it is mentioned below.
Generations of European-history students have been taught that a political assassination caused the First World War. Without some qualification, however, this teaching is bound to mislead, since the war would not have happened without the treaties and alliances that were already in effect and the military force that was already amassed. These were the deeper causes of the war, whereas the assassination was a cause only in a trivial sense. It was like the individual spark that happens to ignite a conflagration that was, in the prevailing conditions, inevitable.
Which one of the following most accurately restates the main point of the passage?
Pre-thinking : The assassination might have been necessary but it sure wasn't sufficient to have caused world war.
(A) The assassination did not cause the war, since the assassination was only the last in a chain of events leading up to the war, each of which had equal claim to being called its “cause.”
The para clearly says the last even wasn't equal. It was just a spark in the already existing dry wood. (B) The war was destined to happen, since the course of history up to that point could not have been altered.
Not relevant
(C) Though the statement that the assassination caused the war is true, the term “cause” more fundamentally applies to the conditions that made it possible for that event to start the war.
Aligns with prethinking. Correct answer.(D) If the assassination had occurred when it did but less military force had at that time been amassed, then the war’s outbreak might have been considerably delayed or the war might not have occurred at all.
Can't infer this from information above.(E) Although the conditions prevailing at the time the war started made war inevitable, if the war had not been triggered by the assassination it would not have taken the course with which students of history are familiar.
This is a TRAP. It used familiar words in the first half of the sentence but in the second half it messes up. Whatever course it took is not our primary concern. We just have to paraphrase the statements above and the last part of the question has a scope out of teh reach of the paragraph.