The answer is A, cause/effect. Marcia is focusing on how the war started, what ended it, and how it affected America. Cause/effect covers all these things, while the other answers either skip over these things completely or concentrate on only a few.
This is best summarized by the third statement. Although the first statement originally looks like the correct answer, if you pay attention to his wording, he says that they will not reconcile while they are fighting, and that their work will become undone by quarrels. The third statement is the most correct.
She returned to her 12th birthday bcuz she thinks it was unimportant. While she was reliving this she realized that all humans are blind. She realized that she took life for granted and did not appreciate the little things. She did not appreciate what she had until she had lost it. In the beginning the other dead people had warned her not to return to the land of the living but she still did it. When she returned she told them "I should have listened to you. That's all human beings are. Just blind people. Thornton wilder is trying to get the readers to appreciate the small things because later on they become things you regret that you did not appreciate.
hope this helps :)
