help plss

How do synonyms best help readers to figure out the meaning of unknown words?

They restate the word in the sentence with another word or words that have a similar meaning.
They provide a word that signals that the author will use a word with the opposite meaning.
They provide an example of the word in the sentence, so readers can support their ideas with details.
They are listed in a dictionary or thesaurus, making it easy to find the meaning of an unknown word.