Which type of policy must be applied on a WAN Edge application-aware firewall to control traffic between two or more VPNs?

A firewall policy, specifically an application-aware firewall policy, is designed to inspect and control traffic flows based on applications, protocols, and ports, and it is the correct mechanism to regulate traffic between different VPNs on a WAN Edge router.

Data policies are used to influence data plane traffic forwarding decisions, such as path selection or QoS, rather than acting as a firewall to permit or deny traffic between VPNs.

Service-insertion policies are used to redirect traffic to external services like firewalls or IPS systems, not to define the firewall rules themselves.

Control policies influence the control plane, affecting routing information and TLOC selection, not directly filtering traffic on the data plane like a firewall.