What is the difference between RADIUS and TACACS+?

A. RADIUS logs all commands that are entered by the administrator, but TACACS+ logs only start, stop, and interim commands.
B. TACACS+ separates authentication and authorization, and RADIUS merges them.
C. TACACS+ encrypts only password information, and RADIUS encrypts the entire payload.
D. RADIUS is most appropriate for dial authentication, but TACACS+ can be used for multiple types of authentication.