Which of the following can be a form of context clue?

A form of context clue is a piece of information within a text that helps the reader understand the meaning of a word or phrase. Synonyms and antonyms serve this purpose effectively. When a synonym is presented, it offers an alternative word with a similar meaning, which can clarify the word in question. Conversely, when an antonym is provided, it highlights what the word does not mean, further enhancing understanding. For instance, if a text uses the word "arduous" alongside terms like "easy" or "simple," the reader can deduce that "arduous" signifies difficulty.

While specific chapter titles, an author's biography, and footnotes and endnotes can provide valuable information about the content or context of a text, they do not directly function as context clues for the meaning of individual words within a passage. Chapter titles might hint at the themes but do not define vocabulary meanings, and an author’s biography gives background information rather than clarifying specific words. Footnotes and endnotes can provide additional information or references but typically do not define vocabulary directly either.