A、Only sellers. B、Only shopkeepers. C、Only buyers. D、Both buyers and sellers. D

Cheques have largely replaced money as a means of exchange, for they are widely accepted everywhere. Though this is very convenient for both the buyer and seller, it should not be forgotten that cheques are not real money: They are quite valueless in themselves. A shopkeeper always runs a certain risk when he accepts a cheque and he is quite within his rights if, on occasion, he refuses to do so.
    People do not always know this and are shocked if their good faith is called into question. An old and very wealthy friend of mine told me he had had an extremely unpleasant experience. He went to a famous jewellery shop which kept a large stock of precious stones and asked to be shown some pearl necklaces. After examining several trays, he decided to buy a particularly fine string of pearls and asked ifhe could pay by cheque. The assistant said that this was quite in order, but the moment my friend signed his name, he was invited into the manager’s office.
    The manager was very polite, but he explained that someone with exactly the same name had presented them with a worthless cheque not long ago. My friend got very angry when he heard this and said he would buy a necklace somewhere else. When he got up to go, the manager told him that the police would arrive at any moment and he had better stay unless he wanted to get into serious trouble. Sure enough, the police arrived soon afterwards. They apologized to my friend for the inconvenience, but explained that a person who had used the same name as his was responsible for a number of recent robberies. Then the police asked my friend to copy out a note which had been used by the thief in a number of shops. The note read: "I have a gun in my pocket. Ask no questions and give me all the money in the safe." Fortunately, my friend’s handwriting was quite unlike the thief’s. He was not only allowed to go without further delay, but to take the string of pearls with him.