Convert the sentence provided below from its passive voice structure to an active voice structure: The rare artefacts had been stored carefully by the curators before the flood occurred.

Explanation

The correct option is (c). The given passive sentence is: “The rare artefacts had been stored carefully by the curators ...” This is Past Perfect Passive (had been + V3). To convert passive to active, we make the agent “the curators” the subject and keep the same tense. Past Perfect active uses: had + V3. Structure: Active voice: Subject + had + V3 + Object + manner/time clause Passive voice: Object + had been + V3 + by + Subject + manner/time clause So the correct active sentence is: “The curators had stored the rare artefacts carefully before the flood occurred.” Option (c) exactly matches. Why other options are incorrect: Option (a): Present Perfect (have stored), not Past Perfect. Option (b): Simple Past (stored), loses the “completed before another past event” meaning. Option (d): Subject-verb agreement error (“has” with plural “curators”) and tense mismatch. So the correct answer is (c)