Crowdsourcing refers to the practice in which a company or organization delegates the work tasks that were usually undertaken by employees to the non-specific social public. Which of the following are not crowdsourcing? ["A toy company has always encouraged and sponsored users to participate in the company's design work. From the robot control system to the building block products, it has received relatively satisfactory results.", 'A detergent company often posts its own R & D projects on major websites, solicits solutions, and gives certain rewards and promises.', 'In the past three years, a real estate company has given all computer, network and peripheral daily maintenance work to a computer company.', 'An art museum invites visitors to write explanations for the exhibits in the museum, and selects some of them to make labels for the exhibition.']