Gig economy: It refers to an economic leader that is composed of freelancers with a small workload. It uses the Internet and mobile technology to quickly match the supply and demand side. It mainly includes two forms of group work and on-demand work through applications. In other words, the previous working relationship was "units-people", but the current mainstream relationship is "platform-people". According to the above definition, which of the following is gig economy? ['Taxi industry.', 'E-commerce Website Maintenance Industry.', 'Takeaway distribution industry.', 'Traffic maintenance volunteer behavior.']