Which type of DNS record should you create?

You have an Azure Active Directory (Azure AD) tenant named contosocloud.onmicrosoft.com. Your company has a public DNS zone for contoso.com. You add contoso.com as a custom domain name to Azure AD. You need to ensure that Azure can verify the domain name.

Which type of DNS record should you create?
A . RRSIG
B . PTR
C . DNSKEY
D . TXT

Answer: D

Explanation:

Create the TXT record. App Services uses this record only at configuration time to verify that you own the custom domain. You can delete this TXT record after your custom domain is validated and configured in App Service.

Explanation: https://docs.microsoft.com/en-us/azure/dns/dns-web-sites-custom-domain