What is the major difference between TACACS+ and RADIUS?

A.
TACAS+ runs in TCP, RADIUS operates in UDP

B.
TACAS+ runs in UDP, RADIUS operates in TCP

C.
RADIUS encrypts the entire body of the access-request packet that is sent from the client to the server, TACAS+ encrypts only the password in the access-request packet

D.
TACACS+ and RADIUS operate on two different protocol layers