Which three items do you recommend for control plane hardening of an infrastructure device? (Choose three.)

Redundant AAA servers improve authentication service availability and resilience but do not directly harden the control plane against traffic-based or protocol-based attacks.

Control Plane Policing (CoPP) rate-limits traffic destined for the device's control plane processor, protecting it from CPU exhaustion and denial-of-service attacks targeting the routing engine.

Warning banners serve a legal and compliance purpose by notifying users of authorized-use policies and have no direct technical effect on control plane security.

Enabling unused services expands the device attack surface - security best practice requires disabling all unused services, not enabling them.

SNMPv3 provides authentication and encryption for network management traffic, preventing unauthorized access, eavesdropping, or tampering with device management communications.

Routing protocol authentication (such as MD5 or SHA for OSPF or BGP) prevents malicious route injection by ensuring only cryptographically verified peers can exchange routing updates.