Option is a financial derivative, which gives the buyer the right to buy or sell the underlying assets at a specific price at a specific time in the future, but it is not an obligation. The buyer can choose to close the position at any time within the validity period of the option according to his own wishes and market conditions. Closing the position refers to the early termination of the option contract, and the buyer or seller can close the position at any time within the validity period of the option. The buyer can sell the option contract at the market price, gain the difference income or bear the difference loss. The seller can buy back the option contract at the market price, cancel the obligation, get the difference income or bear the difference loss.