Why Q signals are three-letter shorthand from international radiotelegraph practice; sent as a statement they give information, sent with a question mark they ask it. QRV means "I am ready" (to receive or to copy), and "QRV?" asks "Are you ready?" It is commonly used in nets and contests to say you are standing by for traffic.
Watch out The other options are all real Q signals, just different ones: QRQ/QRS deal with sending speed (too fast means the other station would ask you to QRS), QRM is interference from other stations, and QRT means I am closing down or quitting.
QRV = "Ready, Very ready." Compare QRM = interference, QRT = shutting down, QRS = slow down.