The sentence that displays correct subject-verb agreement is:
The people in the audience stand as the show ends.
The other sentences have subject-verb agreement errors. Here are the corrections for the incorrect sentences:
- The actors in the play return to take another bow. (Actors is plural, so it should be "return.")
- The dialogue spoken by the actors makes the crowd roar with laughter. (Dialogue is singular, so it should be "makes.")
- The helpers working behind the stage come out, too! (Helpers is plural, so it should be "come.")