Peer education: refers to the use of peers of similar ages, similar knowledge backgrounds and hobbies, friends' opinions and suggestions that are easy to be adopted for related education. Which of the following belongs to peer education? ['Wang, who has a four-year history of drug use, was hired as a volunteer counselor at a drug rehabilitation center after successful drug treatment.', 'The party was held on the university campus, and the organizer specially invited many young artists who the young people liked.', "Han Han's books sell very well on campus.", '"Fans" listen to idols.']