What term is used when you need to confirm that a message was received successfully?

The correct term for confirming that a message was received successfully is "Affirmative." In communication, especially in a law enforcement or emergency response context, an "affirmative" response indicates that the information has been received, understood, and acknowledged. This term is widely used in radio communication protocols to ensure clarity and prevent misunderstandings, which is essential in high-stakes environments.

The other options do not accurately capture this specific meaning. "Relay" refers to passing along a message rather than confirming receipt. "Repeat" suggests reiterating a message for clarity rather than acknowledging its reception. "Out at" typically denotes the finality of a transmission or conversation rather than serving as a confirmation that a message has been understood.