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 D)ignore is correct as the word ignore meansrefuse to take notice of or acknowledge; disregard intentionallyand the word adhere means stick fast to (a surface or substance).
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.