HPE6-A84 topic 1 question 2

Refer to the scenario.
A customer has an Aruba ClearPass cluster. The customer has AOS-CX switches that implement 802.1X authentication to ClearPass Policy Manager (CPPM).
Switches are using local port-access policies.
The customer wants to start tunneling wired clients that pass user authentication only to an Aruba gateway cluster. The gateway cluster should assign these clients to the “eth-internet" role. The gateway should also handle assigning clients to their VLAN, which is VLAN 20.
The plan for the enforcement policy and profiles is shown below:

The gateway cluster has two gateways with these IP addresses:
• Gateway 1
o VLAN 4085 (system IP) = 10.20.4.21
o VLAN 20 (users) = 10.20.20.1
o VLAN 4094 (WAN) = 198.51.100.14
• Gateway 2
o VLAN 4085 (system IP) = 10.20.4.22
o VLAN 20 (users) = 10.20.20.2
o VLAN 4094 (WAN) = 198.51.100.12
• VRRP on VLAN 20 = 10.20.20.254
The customer requires high availability for the tunnels between the switches and the gateway cluster. If one gateway falls, the other gateway should take over its tunnels. Also, the switch should be able to discover the gateway cluster regardless of whether one of the gateways is in the cluster.
You are setting up the UBT zone on an AOS-CX switch.
Which IP addresses should you define in the zone?

A.
Primary controller = 10.20.4.21; backup controller = 10.20.4.22
B.
Primary controller = 198.51.100.14; backup controller = 10.20.4.21
C.
Primary controller = 10.20.4.21; backup controller, not defined
D.
Primary controller = 10.20.20.254; backup controller, not defined