— Could you come back home for dinner?

— ______. I'll be at a very important business meeting at that time. [ ]

A. I think so

B. Yes, I hope so

C. I'm afraid not

D. I'm afraid so

在特殊情况下需使用高于安全电压电源的仪器或机具进入容器工作，必须有严格的安全措施，并经使用单位安全主管负责人批准。