Which DNS record type was originally created to store free-form text in DNS entries for notes or comments?

The correct choice is the Text Record, or TXT Record, which was specifically designed to hold arbitrary text data in the Domain Name System (DNS). Originally, these records served as a way to store notes or descriptive comments that were linked to a domain. For example, administrators could utilize TXT Records to add human-readable information about a domain or for purposes such as SPF (Sender Policy Framework) to indicate which mail servers are authorized to send emails on behalf of the domain.

This functionality distinguishes TXT Records from other types of DNS records. Mail Exchange Records (MX Records) serve the purpose of directing email traffic to the correct mail servers, while Address Records (A Records) map domain names to their corresponding IPv4 addresses. Similarly, AAAA Records, also known as Quad A Records, are used for linking domain names to their IPv6 addresses. While all these records play essential roles in DNS, only TXT Records are unique in their ability to store free-form text, making them the fitting answer for this question.