A、The manufacturer. B、The item of product. C、The selling date. D、The price. C

What are the zebra stripes on the tomato soup cans and potato chip bags? They are special black and white vertical lines. These black and white stripes can be read by an optical scanner, or computer. The "scanner", which reads the lines of code, is a small laser beam of light. When the light ray is broken by the black stripes, the computer "reads" the information about the product.
    This code is called the Universal Product Code (UPC). It is designed to add speed and efficiency to stores by using computers. It can do this in several ways. First, it is not necessary for workers to put individual prices on items. By using UPC, the computer can print out the accurate price of the item. Errors in prices are eliminated, or done away. with. Also, the time spent checking out is reduced. UPC gives an itemized receipt to the customer with all the items, prices, and totals. The store clerk does not need to spend time checking the price on the item and punching it into the cash register. This UPC computerized system will probably save as much as 45 percent of the checkout clerk’s time.
    What do the stripes mean? How does the computer interpret the stripes? The number printed below the vertical bars identifies the manufacturer and the manufacturer’s item. As many as 10 trillion individual machine-readable numbers can be used with this system. In the example, the 0’on the left side means that it is a grocery item. The numbers 51000 indicate the manufacturer. In this case it is the Campbell Soup Company. The last five digits, 00011, mean it is a can of tomato soup. The light rays from the light beam read these lines, and the message is sent directly to the computer. The computer then finds the information about this product (price, inventory data) and sends it instantly back to the terminal at the checkout counter. At the same time, it keeps an inventory for the store manager. Many products have labels with these stripes.