Choose the passive voice form that best expresses the active sentence "Ravi had committed a mistake."

Introduction / Context:
This question tests your understanding of how to change a sentence from active voice to passive voice while keeping the tense and meaning intact. The original sentence is "Ravi had committed a mistake." You must identify which of the options correctly expresses the same idea in passive voice using the appropriate tense and structure.

Given Data / Assumptions:

• Active sentence: "Ravi had committed a mistake."
• Subject in active voice: Ravi.
• Object in active voice: a mistake.
• Tense: past perfect (had committed).
• We must transform it into passive voice without changing the time reference.

Concept / Approach:
To form the passive voice:

• The object of the active sentence becomes the subject of the passive sentence ("a mistake").
• The main verb is changed into a passive form using the appropriate tense of "to be" plus past participle ("had been committed").
• The original subject ("Ravi") is introduced by the preposition "by" at the end.

In the past perfect, the passive structure is "had been + past participle". We must preserve the past perfect meaning to show that the mistake had already been committed before another point in time.

Step-by-Step Solution:
Step 1: Identify tense and structure of the active sentence: "had committed" is past perfect. Step 2: Move the object "a mistake" into the subject position of the passive sentence. Step 3: Create the correct passive verb phrase in past perfect: "had been committed". Step 4: Attach the original subject using "by Ravi" at the end. Step 5: Combine these elements: "A mistake had been committed by Ravi."

Verification / Alternative check:
Examine each option:

• Option A: "A mistake has been committed by Ravi." This is present perfect passive, not past perfect; it changes the time reference.
• Option B: "A mistake had been committed by Ravi." Correctly uses past perfect passive.
• Option C: "A mistake was committed by Ravi." This uses simple past passive, again changing the tense.
• Option D: "A mistake is committed by Ravi." This is simple present passive and clearly wrong for a completed past action.

Only option B preserves both meaning and tense.

Why Other Options Are Wrong:

• A mistake has been committed by Ravi: Present perfect suggests a recent action with present relevance, not necessarily before another past event.
• A mistake was committed by Ravi: Simple past does not emphasise completion before another past reference point, which is the function of past perfect.
• A mistake is committed by Ravi: Suggests a habitual or general truth in the present, which is entirely different.

Common Pitfalls:
Many learners forget to match tenses when forming passive voice and instead focus only on the structure "was + past participle". Another frequent mistake is to ignore the auxiliary "had" when converting past perfect. Always identify the tense first (present, past, perfect, continuous) and then apply the passive pattern for that specific tense. For past perfect, remember "had been + past participle" is the correct passive formation.

Final Answer:
The correct passive voice form is A mistake had been committed by Ravi.