You are the project manager for a complicated construction project which involves building highways in the whole state of North Carolina. You have several groups working with you in the project. To plan resources for this project, you should preferably use a/an ______ .

A．staffing pool description

B．staffing management plan

C．responsibility assignment matrix

D．organization matrix

保养卷烟机磨刀砂轮工作面时，可用（）或铜丝刷蘸无水酒精进行清洁。