Which of the following is an example of a prefix?

A prefix is a morpheme that is added to the beginning of a word to modify its meaning. The choice that represents a prefix from the provided options is "re-," which implies repetition or backward movement when attached to a base word (for example, "redo" means to do again).

The other options represent suffixes or different forms of morphemes. The suffix "-ful" typically indicates "full of" and is used at the end of words (like in "joyful"). "tion" is a suffix that transforms verbs into nouns, indicating an action or state (like "creation"). Lastly, "able" is also a suffix that implies capability when attached to verbs (as in "readable," meaning able to be read). Each of these serves as an ending that alters the meaning of the word but does not function as a prefix. Understanding these distinctions helps clarify the structural components of words in English.