Choose the correct passive voice transformation of the sentence:
Had the meticulous investigators examined all the critical evidence before they closed the case?
Show answer & explanation
Correct answer: B
Explanation
The original sentence is in the past perfect tense ('Had... examined'). To convert this into the passive voice, the structure requires the use of 'had' + 'been' + past participle ('examined'). Option ‘B’ correctly maintains the past perfect tense while transforming the sentence into the passive voice.