With more and more farmers moving to cities, an inadequate labor force is ________ becoming a major factor affecting the country's grain output.

A．automatically

B．occasionally

C．absolutely

D．gradually

( )在工程开工前，负责办理有关施工图设计文件审查、工程施工许可证、组织设计和施工单位认真进行交底和( )。

A．质量监督站；质量监督手续
B．监理单位；土地使用证办理
C．建设单位；土地使用证办理
D．建设单位；质量监督手续