对于一个正常的移动台主叫流程，下面的信令流程先后次序正确的是（） A: OriginationMessage->CMServiceRequest->Allocation->Establish->AssignmentComplete->TchPreamble B: OriginationMessage->CMServiceRequest->TchPreamble->Establish->AssignmentCompleteAllocation C: OriginationMessage->CMServiceRequest->Establish->Allocation->TchPreamble->AssignmentComplete D: OriginationMessage->CMServiceRequest->Establish->AssignmentComplete->Allocation->TchPreamble