A digital transmission standard for encrypting data
A special mode for satellite uplink
An analog fast-scan color TV signal✓الإجابة الصحيحة
A frame compression scheme for TV signals
الشرح
NTSC is the National Television System Committee standard for analog color television used in North America, the format amateurs use for fast-scan TV. It is an analog standard, so the choices describing encryption, compression or a satellite mode are wrong by definition.