Which of the commands below can you use to configure a default route?()
A、A. TK1(config)# ip route 0.0.0.0 0.0.0.0 E0
B、B. TK1(config)# ip route 0.0.0.0 255.255.255.255 S0
C、C. TK1(config-interface)# ip route 255.255.255.255 0.0.0.0 192.168.1.21
D、D. TK1(config)# ip route 0.0.0.0 0.0.0.0 192.168.1.21
E、E. TK1(config)# ip route 0.0.0.0 192.168.1.21 255.255.255.255
F、F. TK1# ip default-network 0.0.0.0 192.168.1.21 255.255.255.255