Final answer:
TACACS+ is similar to RADIUS as both are authentication protocols used in network security for client/server-oriented environments. TACACS+ offers separate authentication, authorization, and accounting services and provides more granular control.
Step-by-step explanation:
Among the choices provided, TACACS+ is the client/server-oriented environment that operates in a manner similar to RADIUS (Remote Authentication Dial-In User Service). Both are authentication protocols used for network security; however, there are some key differences between them. TACACS+ (Terminal Access Controller Access-Control System Plus) provides more granular control over commands that an authenticated user can execute and separates authentication, authorization, and accounting services. On the other hand, RADIUS combines authentication and authorization but is more commonly used due to broader vendor support.