Synonyms are words which have the same or nearly the same meaning in the same language.
Antonyms are words which have opposite meaning in comparison to the other.
Option C)release is correct as the word release means allow or enable to escape from confinement; set freeand the word inhibit means hinder, restrain, or prevent (an action or process).
Both the words are opposite of each other.
The other options are not correct as they do not have the opposite meaning to the given word.