Students are accustomed to a bell ringing to indicate the end of class. The principal replaces it with pop music, and the students quickly respond to the music in the same way. What is the purpose of replacing the bell with pop music?
1) To make the end of class more enjoyable
2) To test the students' reaction to different stimuli
3) To encourage the students to leave the class quickly
4) To create a more modern and dynamic atmosphere in the school
