"Are these positive or negative words?" is the question that should be asked in order to understan an author's tone. Option C is correct.
Tone in writings, stories, or plays refers to the attitude of a writer toward a subject or an audience. Tone is typically conveyed through the choice of words, or the viewpoint of a writer on a particular subject.
In fiction, tone is the narrator’s attitude toward the text while in non-fiction, it is the writer/speaker’s attitude toward his subject.