An Azure AI engineer needs to deploy Azure OpenAI Service so that it is not accessible over the public internet. All traffic must travel over the Microsoft backbone network from the application tier. Which network control achieves this?

B is correct because Azure Private Endpoint creates a private IP address within your VNet that maps to the Azure OpenAI resource, and disabling public network access ensures that all traffic uses this private path over the Microsoft backbone rather than the public internet. The DNS for the Azure OpenAI endpoint must also be configured to resolve to the private IP. A is wrong because IP firewall rules restrict which public IPs can access the service but still route traffic over the public internet; they do not eliminate internet exposure. C is wrong because Azure API Management with WAF adds a management and security layer but still requires the Azure OpenAI endpoint to be accessible, and APIM itself has a public IP unless also using private endpoints. D is wrong because DDoS Protection defends against volumetric attacks but does not prevent public internet access to the resource.