单项选择题
A.[Router-rip-1]undo summary B.[Router-rip-1]undo auto-summary C.[Router-Serial1/0]undo summary D.[Router-Serial1/0]undo auto-summary
A.172.16.0.0/22 B.172.16.0.0/23 C.172.16.0.0/24 D.172.16.0.0/25
A.[Router]rip preference 60 B.R[outer]preference 60 C.[Router-rip-1]rip preference 60 D.[Router-rip-1]preference 60