In your project, you have reason to believe that the current variances occurred because of extraneous factors, and you do not expect similar variances to happen in the future. What should be the estimate at complete for your project BAC=$300,000, AC=$100,000, EV=$150,000, CPI=$1.5 ？（）

A．$250,000.

B．$220,000.

C．$280,000.

D．$200,000.

在Windows 98环境下，用户可以通过“控制面板”中的“添加删除程序”来创建启动盘(软盘)。在Windows 98默认安装的情况下，启动盘上的文件主要来源于c：\windows文件夹下的______文件夹。

A．System

B．Command

C．Config

D．Sysbackup