In theJuniper Mist AI for Wired dashboard, administrators can select one or more switch ports (as shown in the exhibit, e.g., port ge-0/0/25 on an EX4100-48MP). Once configuration changes are made - such as VLAN assignment, port profiles, PoE settings, or administrative state - theSave buttonmust be clicked to confirm and apply those changes to the device.
"When making configuration changes in the Mist switch interface, the Save button must be used to confirm the modifications. Clicking Save applies the selected port settings to the switch through Mist Cloud." Option Ais incorrect: saving does not create a backup. Backups and snapshots are handled through Mist's configuration archive, not via the Save button.
Option Bis incorrect: Save does not reset configuration; instead, it commits changes.
Option Cis incorrect: there is no preview function tied to Save.
Option Dis correct: the Save button is explicitly forapplying configuration changesto the selected switch or port(s).
References:
Juniper Mist AI for Wired - Switch Port Configuration Guide
Juniper Mist AI for Wired - Wired Assurance Administration Guide
Juniper Mist Documentation - Managing Switch Interfaces

Creating a new site requires asite nameandtime zone.
Other parameters (like templates or location data) are optional but recommended for proper reporting.
References:
Mist AI for Wired - Site Creation Workflow
Create a Mist Account and Organization Documentation

Comprehensive and Detailed Explanation From Exact Extract:
InEVPN-VXLANarchitectures, theVXLAN Tunnel Endpoint (VTEP)is the logical interface responsible for encapsulating and de-encapsulating Layer 2 Ethernet frames into VXLAN packets.
Each participating switch - typically the access or distribution node - hosts aVTEPthat maps local VLANs to VXLAN Network Identifiers (VNIs).
When a packet leaves a local VLAN, the VTEP encapsulates it in a VXLAN header and routes it through the underlay IP fabric.
When received at the destination VTEP, the frame is de-encapsulated and delivered to the appropriate local VLAN.
"VTEPs in an EVPN-VXLAN campus fabric perform MAC-to-VNI mapping and encapsulate/decapsulate traffic between virtualized network segments, allowing seamless Layer 2 and Layer 3 connectivity across an IP underlay." References:
Juniper Mist AI for Wired - Campus Fabric EVPN-VXLAN Overview
Juniper Validated Design (JVD): Mist AI Campus Fabric Deployment Guide
Junos OS EVPN and VXLAN Configuration Guide