Which of the following indicates that you are looking for an HF contact with any station?
Why "CQ" is the universal call meaning "seek you," an invitation for any station to answer. The standard HF pattern is a short series of CQs, then "this is" and your call sign given a few times, then release and actually listen before repeating. Repeating your call several times helps stations catch it through QSB and QRM, and pausing to listen is what makes the call useful, since a call no one listens after is just noise. The common "3 by 3" rhythm (three CQs, call sign three times) fits this pattern.
Watch out QTC is the Q signal for "I have a message for you," not a general call, and transmitting an unmodulated carrier serves no identifying purpose and just occupies the frequency.
CQ = "seek you." Call CQ, give your call, then shut up and listen.