1 - Server derived role
2 - User derived role
3 - Authentication default role
4 - Initiation role assigned

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.

Option A: MTU size must be increased beyond the default
This is because option A shows how to configure the MTU size for VXLAN tunnels on Aruba switches using the interface command and the vxlan command. The MTU size must be increased beyond the default value of 1500 bytes to accommodate the VXLAN header and payload2.
Therefore, option A is true regarding a VXLAN implementation on Aruba switches.
Option B: VNIs encapsulate and decapsulate VXLAN traffic
This is also true regarding a VXLAN implementation on Aruba switches. VNIs are used to encapsulate and decapsulate VXLAN traffic between two devices, such as a switch and a server. VNIs are also used to map VXLAN tunnels to overlay networks3.
Therefore, option B is also true regarding a VXLAN implementation on Aruba switches.
VXLAN is a Layer 2 encapsulation technology that substitutes the usage of VLAN numbers to label Ethernet broadcast domains with VXLAN numbers. VXLAN supports 224 Ethernet broadcast domains or VXLAN numbers. A VXLAN number ID is referred to as VNI. There is a one-to-one relationship between an Ethernet broadcast domain and a VNI. A single Ethernet broadcast domain can't have more than one VNI.

802.11mc is a standard that uses Round Trip Time (RTT) and Fine Time Measurements (FTM) to calculate the distance a client is from an AP. 802.11mc defines a protocol for exchanging FTM frames between an AP and a client, which contain timestamps that indicate when the frames were transmitted and received. By measuring the RTT of these frames, the AP or the client can estimate their distance based on the speed of light. The other options are incorrect because they either do not use RTT or FTM or do not exist as standards. Reference: https://www.arubanetworks.com/assets/wp/WP_WiFi6.pdf https://www.arubanetworks.com/assets/ds/DS_AP510Series.pdf