The resource record that allows other servers to deliver Internet mail using SMTP is called; Mail Exchanger (MX)
The correct answer to the blank part of the question is "Mail Exchanger(MX)". This is because a mail exchanger record is simply an MX record that identifies the mail server that has the responsibility of accepting email messages on behalf of a domain name.
Now this Mail Exchanger also operates by allowing other servers to deliver Internet mail with the aid of SMTP(Simple mail transfer protocol)
Read more about SMTP at; https://brainly.com/question/14568877
