Cold chain means that after perishable food is acquired or harvested from the place of production, it is always in the low-temperature environment necessary for the product in all links of product processing, storage, transportation, distribution and retail to ensure food quality and safety, reduce losses and prevent pollution. Special supply chain system. According to the above definition, which of the following is cold chains? ['To maintain the efficacy of the vaccine, put it in a special cryogenic system when transported to use.', 'In order to save energy, the supermarket supermarket canteen sells popsicle refrigerators and stops for 1 hour every 5 hours.', 'Use refrigerated trucks to transport fresh seafood to cold stores.', 'A plant uses low-temperature deep extraction technology to make oranges into orange juice for storage at room temperature.']