Explanation
The show arp command displays the ARP table for a specific VRF or all VRFs on the switch. The ARP table contains the IP address to MAC address mappings for hosts that are directly connected to the switch or reachable through a gateway. If the client device is connected to another switch by VSX LAG, the ARP entry for the client device will not be present on the primary switch unless it has communicated with it recently.
Therefore, to find the IP address of the client device, the administrator should run the show arp command on the secondary switch in the VSX pair, specifying the VRF name that contains the client device's subnet.
References:
https://techhub.hpe.com/eginfolib/Aruba/OS-CX_10.04/5200-6692/GUID-9B8F6E8F-9C7A-4F0D-AE7B-9D8E

Explanation
Active Gateway is the first-hop protocol feature that is used for VSX L3 gateway as per Aruba recommendation. Active Gateway is a feature that allows both VSX peers to act as active gateways for different subnets, eliminating the need for VRRP or other first-hop redundancy protocols. Active Gateway also provides fast failover and load balancing for L3 traffic across the VSX peers. The other options are incorrect because they are either not recommended or not supported by Aruba CX VSX. References:
https://www.arubanetworks.com/techdocs/AOS-CX/10.04/HTML/5200-6728/bk01-ch07.html
https://www.arubanetworks.com/resource/aruba-virtual-switching-extension-vsx/

Explanation
To onboard a new UXI in an existing environment with 802.1X authentication, you need to use the UXI app on your smartphone and connect the UXI via Bluetooth. The UXI app allows you to scan the QR code on the UXI sensor and configure its network settings, such as SSID, password, IP address, etc. The Bluetooth connection allows you to communicate with the UXI sensor without requiring any network access or cellular connection. The other options are incorrect because they either do not use the UXI app or do not use Bluetooth. References:
https://www.arubanetworks.com/products/network-management-operations/analytics-monitoring/user-experienc
https://help.centralon-prem.arubanetworks.com/2.5.4/documentation/online_help/content/nms-on-prem/aos-cx/g

Explanation
To create a new OSPF configuration for a separate routing table, you need to create a new OSPF process ID with vrf name. This will create a new OSPF instance that is associated with the specified VRF and its routing table. The other options are incorrect because they either do not create a new OSPF instance or do not associate it with a VRF. References:
https://www.arubanetworks.com/techdocs/AOS-CX/10.04/HTML/5200-6728/bk01-ch02.html
https://www.arubanetworks.com/techdocs/AOS-CX/10.04/HTML/5200-6728/bk01-ch03.html

Explanation
To address the situation of unencrypted tunnels between the CX switch and the Aruba Gateway, the administrator must enable Enhanced security on both devices. Enhanced security is a feature that provides encryption and authentication for GRE tunnels between CX switches and Aruba Gateways using IPSec.
Enhanced security can be enabled globally or per tunnel on both devices using CLI commands or Web UI options. The other options are incorrect because they either do not provide encryption or authentication for GRE tunnels or do not exist as features. References:
https://www.arubanetworks.com/techdocs/AOS-CX/10.04/HTML/5200-6728/bk01-ch05.html
https://www.arubanetworks.com/assets/ds/DS_AOS-CX.pdf