Box 1: Scale set -
A virtual machine scale set allows you to deploy and manage a set of identical, autoscaling virtual machines.
Box 2: Availability Set -
An Availability Set is a logical grouping capability for isolating VM resources from each other when they're deployed. Azure makes sure that the VMs you place within an Availability Set run across multiple physical servers, compute racks, storage units, and network switches. If a hardware or software failure happens, only a subset of your VMs are impacted and your overall solution stays operational. Availability Sets are essential for building reliable cloud solutions.
Box 3: Fault domain -
A fault domain is a logical group of underlying hardware that share a common power source and network switch, similar to a rack within an on-premises datacenter. As you create VMs within an availability set, the Azure platform automatically distributes your VMs across these fault domains. This approach limits the impact of potential physical hardware failures, network outages, or power interruptions.
Incorrect Answers:
An update domain is a group of VMs and underlying physical hardware that can be rebooted at the same time.
References:
https://docs.microsoft.com/en-us/azure/virtual-machines/windows/tutorial-create-vmss https://docs.microsoft.com/en-us/azure/virtual-machines/windows/tutorial-availability-sets