`Who has done the work?` The correct passive form of the sentence is ——.
Who is the work done by?
The work has done by whom?
By whom has the work done?
By whom has the work been done?
Explanation:
Correct Answer is: By whom has the work been done?

Who is the work done by?
The work has done by whom?
By whom has the work done?
By whom has the work been done?
Correct Answer is: By whom has the work been done?

I water the plants. The word `water` is used as- Option A: verb , Option B: adverb , Option C: Noun, Option D: Pronoun, correct answer is: verb
Identify the word that can be used as both singular and plural: Option A: wood , Option B: issue , Option C: fish, Option D: light, correct answer is: fish
`He pocketed the money.` In the sentence, the word `pocketed` has been used as a/an . Option A: Noun , Option B: Verb , Option C: adverb, Option D: Preposition, correct answer is: Verb
I have told you twice. Here `Twice` is- Option A: Adverb , Option B: Adjective , Option C: Noun, Option D: Preposition, correct answer is: Adverb
There has been a breakthrough in the treatment of dengue patients. Here `breakthrough` is a/an- Option A: adjective , Option B: verb , Option C: noun, Option D: adverb, correct answer is: noun