Active-to-passive voice (modal perfect): Convert the sentence to the correct passive that preserves the perfect modal sequence. Source sentence: A child could not have done this mischief. Instruction: Choose the grammatically correct passive-voice option.

Given data

• Active sentence: A child could not have done this mischief.
• Target: Passive with modal perfect.

Concept / ApproachPassive with modal perfect: modal + have + been + past participle.

Step-by-step transformationObject becomes subject: this mischief → This mischiefApply modal perfect passive chain: could not have been doneAgent in by-phrase: by a childFinal passive: This mischief could not have been done by a child.

Eliminate wrong optionsA: Uses could not be done (simple modal), loses perfect aspect. ❌B: Omits have before been; ungrammatical. ❌C: Matches modal perfect passive exactly. ✅D: Word order is incorrect and ungrammatical. ❌

Common pitfalls

• Forgetting have in the perfect passive chain.
• Changing aspect or tense unintentionally.

Final AnswerThis mischief could not have been done by a child.