Select the most appropriate ANTONYM of the highlighted word.
Technology plays an indispensable role in the lives of human beings in the 21^st century.

Correct option is A

Indispensable means something that is absolutely necessary or essential.
• Synonyms: vital, crucial, necessary, important.
• Antonyms: unnecessary, dispensable, nonessential, superfluous.
Meanings of other options:
• Superfluous: something that is extra or unnecessary, exceeding what is necessary or required.
• Relentless: something that is unyielding or harsh, persistent in pursuing something.
• Unprecedented: something that is never seen before, unique or unparalleled in nature.
• Vigilant: keeping careful watch for possible danger or difficulties.