The thesis should be changed to D: “The life of the typical college student is characterized by time spent studying, attending class, and socializing with peers.”
D is the correct option because it gives a list of what will be included in paragraphs to come. It is always a good idea to create this type of list in your thesis.
No, it is not a run on sentence.
If it comes from "Civil Peace" by Chinua Achebe to he answer is that he feels lucky if his family is alive and has access to the basic necessities of life.
He used to be bitter about his position in life, but now he is optimistic no matter what happens.
He used to be optimistic about life, but losing a son has made him bitter and resentful.
He has not been affected by the Nigerian Civil War because he was out of the country until it was over.