如果投资者预期两份合约之间的价差将收窄，他将启动价差（）

• A、selling the contract offered at the higher price and selling the contract offered at the lower price
• B、buying the contract offered at the higher price and buying the contract offered at the lower price
• C、buying the contract offered at the higher price and selling the contract offered at the lower price
• D、以较高的价格出售合同，以较低的价格购买合同