Futures arbitrage trading includes spot arbitrage and spread arbitrage. If the spread between the futures market and the spot market is used for arbitrage, it is called spot arbitrage; If the spread between different contracts in the futures market is used for arbitrage, it is called spread trading or hedging profit. Item a refers to hedging; In item B, the purpose of futures arbitrage is to obtain spread profits, and the purpose of hedging is to avoid risks, which are usually not combined; Item C When the futures price is higher than the spot price,

When the degree is far less than the normal level, you can sell the spot and buy the relevant futures contracts to make a profit; Item d refers to spot arbitrage.