T1F08

What is the definition of third-party communications?

1. AA message from a control operator to another amateur station control operator on behalf of another person
2. BAmateur radio communications where three stations are in communications with one another
3. COperation when the transmitting equipment is licensed to a person other than the control operator
4. DTemporary authorization for an unlicensed person to transmit on the amateur bands for technical experiments

Pick an answer to check it.