Answer would be conflict. Antagonist is essentially the protagonist's enemy.
I have read "The Things They Carried" by Tim O'Brien. This story is a fictional story about a young man who was drafted for the Vietnam war in his first years of college. This book describes the coming of age of multiple characters in its portrayal of each character individualistically. It shows how fast each of these young men had to grow up after joining the war and the difficulties they faced. It is easy to forget how young these guys are because of the things they say or the actions they must take. There are many moments in the book that make you stop and go "Hey wait. These are just kids," and it really shows the maturing process and the stresses of war in addition to suddenly being thrust into adulthood.
We should read stories to become our best self. Stories inspire us to become better and more like the characters we read about. Stories and characters help explain what we should and should not do/be like. We should care because stories have been passed down from generations so that way we can learn the morals hidden in them. All stories have an underlying moral that can greatly impact your life and help you look at the world in a new way
D. If it's too hard to read, then you should shorten some sentences to give the sentence more of a flow.