The aquarium is going to give away bouncy balls to all visitors under the age of 18 for a month after the twin baby stingrays are born. In the spirit of giving visitors an opportunity to do so, What is the purpose of giving away bouncy balls?
1) To entertain the visitors
2) To celebrate the birth of the twin baby stingrays
3) To encourage visitors to visit the aquarium
4) To promote interaction and playfulness among visitors