What does an eponymous character mean?

The correct answer is: An eponymous character gives his or her name to the title of the work

Detailed Explanation:
The term "eponymous" originates from the Greek word epōnymos, which literally means "giving name" or "named after." In the context of literature, theater, television, and film, an eponymous character is a character who gives their name to the title of the work in which they appear.

For example, in William Shakespeare's play Hamlet, the main character is Hamlet; thus, Hamlet is the eponymous character. Other famous examples include Harry Potter in the Harry Potter series, Jane Eyre in Charlotte Brontë's novel Jane Eyre, and Robinson Crusoe in Daniel Defoe's Robinson Crusoe.

The other choices are incorrect because the word "eponymous" refers strictly to the naming relationship between the character and the work's title, rather than describing the character's personality traits (such as being devilish or intriguing) or their structural function in the plot (such as being superfluous).