Which command is useful when troubleshooting AAA Authentication between a Cisco router and the AAA server?

Which command is useful when troubleshooting AAA Authentication between a Cisco router and the
AAA server?

A.
test aaa‐server test cisco cisco123 all new‐code

B.
test aaa group7 tacacs+ auth cisco123 new‐code

C.
test aaa group tacacs+ cisco cisco123 new‐code

D.
test aaa‐server tacacs+ group7 cisco cisco123 new‐code