Service public relations: Public relations activities in order to gain the public's understanding and praise, establish a good image of the organization, and provide consumers with various affordable services. Which of the following are service public relations? ['A refrigerator manufacturer regularly sends new information on food storage and freshness to customers.', 'A company regularly announces product development and sales with the help of posters and company websites.', 'A tent manufacturer donated hundreds of tents to an earthquake-stricken area in time.', 'Consumers of a well-known brand build their own QQ group to exchange experiences.']