According to the Aruba Documentation Portal1, user-based tunneling (UBT) is a feature that uses GRE to tunnel ingress traffic on a switch interface to a gateway for further processing. UBT enables a switch to provide a centralized security policy, using per-user authentication and access control to ensure consistent access and permissions.
Option A: The switch will put the client on the access VLAN This is because option A shows how UBT works on an Aruba switch. When a device connects to the network, it is authenticated using either MAC Authentication or 802.1X and triggers an enforcement policy from ClearPass, which contains an enforcement profile with a user role configuration. The user role can be assigned locally on the switch or on ClearPass as part of an enforcement profile. The user role determines the VLAN that the device belongs to and the access policies that apply to it.