Antonym of VOLUNTARY

A. ordered

B. alternative

C. compulsory

D. essential

Answer: Option C

Solution(By Examveda Team)

Voluntary : done, given, or acting of one's own free will.
Ordered : give an authoritative instruction to do something.
Alternative : (of one or more things) available as another possibility or choice.
Compulsory : required by law or a rule; obligatory.
Essential : absolutely necessary; extremely important.

Antonym of Voluntary is Compulsory