You have two subscriptions: Sub1 contains VM1 and Sub2 will host resources that need access to VM1 via Azure Private Link. To enable creation of a Private Link service that exposes VM1 to Sub2, what must you first configure in Sub1?

To expose a virtual machine (VM) via Azure Private Link Service, the VM must be behind an Azure Standard Load Balancer. The Private Link Service uses the Load Balancer's frontend IP configuration to create the private link. Therefore, configuring an Azure Load Balancer in Sub1 is a prerequisite. An Azure Private DNS zone is used for name resolution with private endpoints, not for exposing the service itself. A service endpoint secures access to Azure services over the Azure backbone, but it doesn't enable exposing a custom service via Private Link. A private endpoint is the consumer-side component that connects to a Private Link service, not the provider-side component for exposing the service.