By this time tomorrow ,I bet the contract___ A has been prevented B will have been signed

问题描述:

By this time tomorrow ,I bet the contract___ A has been prevented B will have been signed
C is signed D will be signed请说明理由

B为什么由tomorrow可知时间是将来,再有by后接时间,可知要用完成时,所以综合起来就要用将来完成时不好意思啊,答案是D我还是认为答案应该是B