What is the best way to confirm that AAA authentication is working properly?

A.
use the test aaa command

B.
use the Cisco-recommended configuration for AAA authentication

C.
Log into and out of the router, and then check the NAS authentication log

D.
Ping the NAS to confirm connectivity

Explanation:
The other choices do not verify functionality.
There is a test aaa command in IOS, just tried it in my lab:
R1#test aaa group radius admin cisco123 new-code
User successfully authenticated
USER ATTRIBUTES