Answer: B) Serious.
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 excerpt from "Ain't I a Woman" we can see an example of a serious tone, we can know that by looking at the exclamation points, that make the statement stronger and more serious.