Why is TACACS+ the preferred AAA protocol to use with Cisco device authentication?

A.
TACACS+ encryption algorithm is more recent than other AAA protocols

B.
TACACS+ has a more robust programming interface than other AAA protocols

C.
TACACS+ was initially developed as open-source software

D.
TACACS+ provides true AAA functional separation and encrypts the entire body of the packet

E.
TACACS+ maintains authentication information in the local database of each Cisco IOS router

F.
TACACS+ combines authentication and authorization to provide more robust functionalities