Given the following routing table
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.178.0 0.0.0.0 255.255.255.0 U 9 0 0 wlan0
Why does the command route add default gw 192.168.1.1 fail?

A.
Because there is no route to 192.168.1.1.

B.
Because only one route can exist at a time.

C.
Because there is already a default route.

D.
Because default routes can not be set manually.

E.
Because default routes must be set with ifconfig.

Explanation: