Which of the following commands can be used to add a default gateway to a host?

Which of the following commands can be used to add a default gateway to a host?

A.
route add 0.0.0.0 gw 192.168.1.1

B.
traceroute -d 192.168.1.1

C.
ping -s 1 192.168.1.1

D.
ifconfig eth0 192.168.1.1 255.255.255.0