What is true regarding a default route?

What is true regarding a default route?

A.
The default route is only used if there is not a more specific route to a destination host or network.

B.
Without a default route, no network communication even in directly attached networks is possible.

C.
When a default route is set, all other routes are disabled until the default route is deleted.

D.
The default route is always used first. When the default route is not available more specific routes are tried.