How can an administrator determine if a router has been configured when it is first powered up?

A.
A configured router prompts for a password.

B.
An unconfigured router goes to the enable mode prompt.

C.
A configured router goes to the privileged mode prompt.

D.
An unconfigured router goes into the setup dialog.

Explanation:
If a non-configured router is started, then it goes into setup mode and ask for the minimum
configuration parameters (hostname, IP address to interfaces, enable password, etc). If the router
is already configured it boots by implementing the saved startup-config.