Select the most appropriate ANTOMYM of the word established from the given sentence:
Siben feels great satisfaction and gratified when he finds his pupils established successfully in the society when a lot have been displaced because of several failed attempts.

Correct option is A

The word " established" means to set up or create something successfully, while " displaced" means take over the place, position, or role of. Therefore, "displaced" is the correct antonym of "established" in the given context.
Synonyms: confirmed, settled, recognized, traditional.
Antonyms: experimental, unestablished, unknown, untested.
Meanings of other three options are as follows:
Fail - to be unsuccessful or not meet expectations.
Gratified - feeling pleased and satisfied.
Pupils - students in school.