Which of the following types of security services are used to support authentication for remote users and devices?

Biometrics refers to authentication using physical characteristics such as fingerprints or retinas, which is an authentication factor type, not a network protocol that supports centralized remote authentication.

A Hardware Security Module (HSM) is a physical device that safeguards cryptographic keys and performs cryptographic operations; it does not provide authentication services for remote users.

RADIUS (Remote Authentication Dial-In User Service) is a client-server networking protocol that centralizes AAA services for users and devices connecting remotely, such as via VPN or wireless networks. It is widely supported across vendors and is the industry-standard service specifically designed for remote access authentication scenarios.

TACACS+ is primarily used for privileged administrative access control to network devices rather than broadly for remote end-user authentication the way RADIUS is.