Which TrustSec feature supplies scalable, secure communication by assigning tags?

Cisco TrustSec uses Security Group Tags (SGTs) to provide scalable, secure communication. An SGT is a 16-bit tag assigned to a user or device upon authentication, typically at the access layer (e.g., a switch port). This SGT identifies the security group to which the user or device belongs. Instead of configuring traditional IP-based ACLs on every device, TrustSec applies policies based on these SGTs, allowing for consistent enforcement across the network regardless of IP address changes. The SGT is carried with the traffic, enabling policy enforcement at various points. The other options are incorrect because: "security group tag ACL assigned to each port on a switch" misrepresents SGTs; SGTs are tags, not ACLs, and policies are based on SGTs, not ACLs assigned to ports. "security group tag number assigned to each port on a network" is partially correct as SGTs are associated with ports, but the primary assignment is to the authenticated user/device, not just the port itself. "security group tag ACL assigned to each router on a network" is incorrect because SGTs are not ACLs and are not primarily assigned to routers for policy definition.