Why is the group tag in the aaa-server command important?

Why is the group tag in the aaa-server command important?

A.
The group tag enables or disables user authentication services.

B.
The group tag identifies which user groups must authenticate.

C.
Theaaa command references the group tag to know where to direct authentication,
authorization, or accounting traffic.

D.
The group tag identifies which users require authorization to use certain services.