C is the correct answer, because if a written assignment is a 'humorous report', it means that it can be subjective, and that the author's personality is noticeable in the text. Whereas that is not the case in the other options.
She kills herself because they couldn't be together anymore
Huck goes along with Tom's crazy plans because he wants to be noticed and missed. He also doesn't want to let his friend down or disappoint him.
I think the central idea is The people