Answer: D) optimistic.
Step-by-step explanation: The tone of a text or sentence is the author's or speaker's attitude towards the audience, the subject or even the characters of the text. There are many different kinds of tones, like: positive, negative, objective, sad, angry, etc. In the given sentence we can see an example of an optimistic tone. Optimistic means being hopeful and confident about the future, so good prevailing over evil is optimistic.