Select the most appropriate ANTONYM of the given word.

Optional

Compulsory

The most appropriate antonym of the given word optional is compulsory.

• Optional means something that can be chosen or not chosen.
• Compulsory means something that must be done or taken.

The word optional means something that can be chosen or not chosen, while the word compulsory means something that must be done or taken. Therefore, the antonym of optional is compulsory.

The other options are not antonyms of optional.

• Voluntary means done or undertaken of one's own free will.
• Arbitrary means based on personal whim or preference rather than on reason or system.
• Elective means chosen or selected by oneself.