North Korean（朝鲜）leader Kim Jeong-eun has sent urgent messages to world leaders Saturday, ________ that the United Nations’ decision on North Korea was ________.

A．claiming; valid

B．claimed; valid

C．claiming; invalid

D．claimed; invalid

下列关于DCS现场准备工作说法正确是（）

A.系统位置的选择，机房的布置，环境的要求

B.供电系统的准备

C.I\O信号线的铺设

D.系统接地的设计和安装