单选题
在某园区网中,路由器RA的GE0/1(196.28.57.5/30)与路由RB的GE0/1(196.28.57.6/30)相连,RB的GE0/2(196.28.57.9/30)与路由器RC的GE0/1(196.28.57.10/30)相连,RC路由器的GE0/2(196.28.57.13/30)直接连Internet上的路由器相连,路由器RA访问Internet默认路由的正确配置是 A) ip route 0.0.0.0 0.0.0.0 196.28.57.6 B) ip route 0.0.0.0 0.0.0.0 196.28.57.9 C) ip route 0.0.0.0 0.0.0.0 196.28.57.10 D) ip route 0.0.0.0 0.0.0.0 196.28.57.13