Questions 11 to 13 are based on the following talk on different superstitions and customs. You now have 15 seconds to read Questions 11 to 13. Why is it necessary to give a coin to someone when you give him a present with a sharp edge or point
A．To specially celebrate his birthday. B．To express some special meaning which you dare not tell directly. C．To wish for a long-lasting friendship. D．To wish your friend good luck in his life.