Part of the configuration files for routers testking1 and testking2 are displayed below:<img src="https://nimg.ppkao.com/2018-07/longzhengxuan/2018073011533176465.jpg?sign=b431075463d67d227d1744b2491e0e33&t=62d455aa" /><br /> If you were to enter the "show interface serial 0" command on router testking1,which of the following will be displayed?()
A、Serial 0 is down, line protocol is down
B、Serial 0 is up, line protocol is up
C、Open: IPCP, CDPCP
D、LCP closed
E、LCP open