Which of the following is included in packet radio transmissions?

Packet radio operates much like the internet, breaking larger messages into small, manageable blocks of data called 'packets.' Every packet requires specific components to ensure it reaches its destination intact. A packet includes a header containing routing information, such as the call signs of the sender and the recipient. It also includes a checksum at the end, which the receiving station uses to mathematically detect any data corruption that occurred over the air. If the checksum indicates an error, the receiving station uses Automatic Repeat reQuest (ARQ) to ask the sending station to transmit that specific packet again. Because all these elements are essential to the protocol, 'All these choices are correct' is the right answer.