DNS レコードに含まれる事前に合意されたコンテンツの存在を確認することにより、ドメインの所有権を検証するために使用できるのは次のうちどれですか?
正解:D
Explanation "One final usage of the TXT resource record is how some cloud service providers, such as Azure, validate ownership of custom domains. You are provided with data to include in your TXT record, and once that is created, the domain is verified and able to be used. The thought is that if you control the DNS, then you own the domain name."