Which of the following is required when making on-the-air test transmissions?

When making on-the-air test transmissions, the FCC requires that you properly identify your station just as you would during normal communications. An unidentified signal is considered illegal interference, even if it is just a brief test. Distractors like restricting tests to certain nighttime hours or notifying the FCC are completely fabricated rules. As long as you give your call sign at the required intervals and ensure the frequency is clear before transmitting, you can conduct test transmissions at any time.