Answer:
B. The tone is the author's attitude toward the subject.
Step-by-step explanation:
In literature, the tone of a text expresses the writer's feelings about the subject matter. It goes without saying that the writer's feelings about the subject are reflected in his or her attitude toward this subject. In other words, if the author feels good about something or someone depicted in his or her literary work, the tone created in the text will show the author's positive attitude to the things or characters (s)he's is describing.
Therefore, the correct answer would be attitude toward the subject.