Identify the sentence in Passive Voice.

The correct answer is Option (4) → The concert has been postponed.

Passive voice:

• The subject receives the action instead of doing it.
• The verb is a form of be + past participle.
• "The concert has been postponed": the concert does not postpone anything; someone postponed it. "Has been postponed" is the present perfect passive.
  Example: The match has been cancelled because of rain.

Why the Other Options are Incorrect?

Option 1: The concert is continuing. — Incorrect. "Is continuing" is the present continuous active; the verb has no be + past participle form, and "continue" is used here without an object.

Option 2: The concert held at the new auditorium was superb. — Incorrect. "Held" is a participle that only describes the concert; the main verb is "was" + the adjective "superb", which is not a passive verb.

Option 3: We enjoyed the concert. — Incorrect. The subject "we" does the action; it is active.