Cartel, a form of monopoly organization, refers to capitalist enterprises in the same production sector. In order to obtain high monopoly profits and strengthen their position in competition, they sign agreements with each other on the sales market, commodity output, and commodity prices, and A monopoly union formed by the exchange of licenses for new technologies. Which of the following are not cartels? ['Each producer signs an agreement stipulating the sales market.', 'Each producer signs an agreement specifying monopoly prices.', 'Each producer signs an agreement stipulating a certain quantity of goods to be produced and sold, and requires each participant to comply.', 'Due to cost accounting, businesses have stopped discounting competition.']