Final answer:
a) Verify domain ownership by adding a DNS record. To take ownership of a domain name in Azure Active Directory, you need to verify domain ownership by adding a specific DNS record to your domain's DNS settings for verification by Azure.
Step-by-step explanation:
In order for Azure Active Directory to take ownership of a domain name, the correct action to perform is a) Verify domain ownership by adding a DNS record. This process typically involves adding a TXT or MX record to the domain's DNS settings to prove to Microsoft that you have administrative control over the domain.
You do not need to transfer domain ownership to Microsoft, send a written request to Azure support, or expect the process to happen automatically. Once the DNS record has been added and verified by Azure, the domain will be considered owned by the account's Azure Active Directory, enabling you to manage the domain and associated services within the Azure environment.