What is the correct Q code to ask who is calling you?

In amateur radio, Q codes are three-letter combinations originally created for Morse code to standardize and speed up communication. "QRZ?" specifically means "Who is calling me?" and is commonly used after a CQ call when a station hears a response but cannot quite make out the full call sign. The other options have very different and specific meanings. "QRL?" asks if the frequency is busy, "QRT?" asks if a station should stop transmitting entirely, and "QSL?" asks for an acknowledgment of receipt.