Concept:The correct spelling of the word meaning "done willingly" is "Voluntary".Explanation:Option A "Voluntary" has all letters in the right order. Option B "Voluntry" misses the letter 'a' after 't'. Option C "Volontary" replaces 'u' with 'o'. Option D "Vouluntary" swaps the 'o' and 'u'. Break the word into syllables: Vol-un-ta-ry. Only "Voluntary" follows standard English spelling.Answer:A. Voluntary