7871. Silence is mandatory for meditation to be effective.

✅ The correct answer is option A.
compulsory : required by law or a rule; obligatory.

optional : available to be chosen but not obligatory.

voluntary : done, given, or acting of one’s own free will.

permissive : allowing or characterized by great or excessive freedom of behaviour.

mandatory : required by law or mandate; compulsory.

Synonym of mandatory is compulsory