Jim is one of my closely friends. Two months ago, his mother bought a computer to him as a birthday present. She hoped Jim will study hard with the help of the computer. To his surprise, Jim just wasted plenty of time play computer games every day. Now she regrets buying the computer. As matter of fact, a computer can do a lot of everyday jobs for us. It is wide used in factories, hospitals, banks and so on. Many computers scientists are now trying to make the computer to “think” like a man. In my opinion, the key is what we should use it wisely.

市场交易的组织形态，根据交易合约的签订与实际交割之间的关系分为（）。

A．现货交易

B．远期交易

C．期货交易

D．短期交易