A、Because they usually can’t see the actual product. B、Because it is the law. C、Because salespeople can’t be trusted. D、Because

Are you familiar with large supermarkets? If so, then you probably know that almost everything in the market is in a container. Most food is in containers. Even fresh meat is sold in plastic packages. [22]Fresh fruit and vegetables are usually the only food items that don’t come in containers. In fact, almost everything at the supermarket is in a bag, a box, a bottle, a jar, a carton, or a can.
    This kind of packaging system is necessary at large supermarkets. Supermarkets buy large quantities of everything. Products must be protected during shipment and they must sit on shelves for long periods of time. [23]Containers, therefore, protect the products. Containers have another function, too. They give information about each product— [24]names, weights, materials, and ingredients, and sometimes pictures of the products. This information is printed on labels or directly on the containers.
    But think of this, we never see most of the things we buy at the supermarket until we get home and open the containers. When we go shopping, we look at the labels on the containers. If the container is made of glass or clear plastic, perhaps we could see a little bit of the product. [25]But usually containers completely hide their products. Shoppers must trust the labels.
Questions 22 to 25 are based on the passage you have just heard.
22. Which of the following is usually not sold in containers at large supermarkets?
23. What are the functions of containers?
24. Which of the following doesn’t need to be printed on labels?
25. Why must shoppers trust labels?