C. The author's attitude about the topic of the poem.
Explanation:
The tone in literature is the attitude of the writer about a topic, or anything in the text. It is conveyed through the use of words, sounds, or even diction.
An author can convey his thoughts or attitude through the many elements of his writing. And this tone can be in many forms, be it formal or informal, sarcastic, serious, sad, comic, or even horrific.
