Which of the following is a peor entity authentication method for Point-to-Point Protocol (PPP)?

Challenge Handshake Authentication Protocol (CHAP) is defined in RFC 1994 as an authentication method specifically designed for PPP connections. It uses a three-way handshake mechanism where the authenticator sends a challenge to the peer, the peer responds with a hash value, and the authenticator verifies the response. CHAP is one of the two primary peer entity authentication protocols for PPP, alongside PAP.

Message Authentication Code (MAC) is a cryptographic technique used to verify data integrity and authenticity of messages, not a peer entity authentication method for PPP.

Transport Layer Security (TLS) handshake protocol operates at the transport layer to establish secure sessions for applications like HTTPS, and is not a PPP peer authentication method.

Challenge-response authentication mechanism is a general authentication concept or category, not a specific PPP peer entity authentication protocol like CHAP is.