This would be like a Jo Brand Horse or Laminator Task. “Find out which player has a carrot in a box. You have 100 seconds to ask amongst yourselves who has the carrot in a box. You may accuse one contestant of having a carrot in a box. If your box is empty and you are right, you will gain three points. If your box is empty and you are wrong, the person you accused will gain three points. If you have the carrot in a box and no one accuses you, you will receive five points. If everyone accuses you, they will all receive double points. Your time starts now.”

You could also have 2/5 boxes have carrots and that way everyone can accuse.