Option C is a part of the solution because it defines a policy-based routing action list named route_test, which specifies the next hop IP address as 10.1.1.253 for the matching traffic. This is the new default route that the user wants to use for the subnet 10.2.250.0/24. The interface null parameter indicates that the traffic will be routed to the next hop without using a specific interface.
Option E is a part of the solution because it applies the policy-based routing action list route_test to the VLAN interface 250, which has an IP address of 10.2.250.1/24. This is the subnet that the user wants to test the new default route for. The apply policy command enables policy-based routing on the interface and associates it with the action list.

Explanation
UDLD (Unidirectional Link Detection) is the information that the Inter-Switch Link Protocol configuration uses in the configuration created for Aruba CX VSX pair inter-switch-link. UDLD is a protocol that detects unidirectional links between switches and prevents loops or black holes in the network. UDLD is enabled by default on all ports that are part of the inter-switch-link between VSX peers. The other options are incorrect because they are either not related to inter-switch-link 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/techdocs/AOS-CX/10.04/HTML/5200-6728/bk01-ch02.html

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.

Explanation
configures DHCP snooping on the switch and enables it for VLANs 100, 110, and 120. It also specifies the IP address of the authorized DHCP server and sets the ports connected to the server as trusted. This prevents any unauthorized DHCP server from providing invalid configuration data to the clients on those VLANs. Option B also enables DHCP option-82, which adds information about the switch port and VLAN to the DHCP packets, allowing for more granular control and logging of DHCP transactions.

The correct answer is C. sysops.
The sysops user role is a predefined role that allows users to view switch configuration information and have access to the PUT and POST methods for REST API. The sysops user role can also use the PATCH and DELETE methods for REST API, but not for all resources. The sysops user role is suitable for users who need to perform system operations on the switch, such as backup, restore, upgrade, or reboot.
According to the AOS-CX REST API Reference basics1, one of the predefined user roles is: sysops:
Users with this role can view switch configuration information and have access to the PUT and POST methods for REST API. They can also use the PATCH and DELETE methods for REST API, but not for all resources. Users with this role can perform system operations on the switch, such as backup, restore, upgrade, or reboot.
The other options are incorrect because:
A) administrators: Users with this role have full access to all switch configuration information and all REST API methods. This role is more than what the customer requires.
B) auditors: Users with this role can only view switch configuration information and have access to the GET method for REST API. They cannot use the PUT and POST methods for REST API.
D) helpdesk: Users with this role can view switch configuration information and have access to the GET method for REST API. They can also use the PATCH method for REST API, but only for a limited set of resources. They cannot use the PUT and POST methods for REST API.