Final answer:
In a sliding window Go-Back-N ARQ system, upon receiving packet 3 corrupted, B should send a REJ-3 message and A should resend packets 3, 4, 5, 6, 7, 0 and 1 to maintain the window size, making option a the correct choice.
Step-by-step explanation:
In a sliding window Go-Back-N ARQ system, if a packet arrives corrupted at the receiver, the receiver typically sends a reject (REJ) message back to the sender indicating at which packet the error was detected. This prompts the sender to retransmit the erroneous packet and all subsequent packets that were sent after the erroneous one. Given that packet 3 arrives at receiver B corrupted, B should send a REJ message for packet 3. In response, A should resend packets 3, 4, 5, and 6. Some implementations might continue to send additional packets to maintain the window size.
If we assume the correct interpretation of the sliding window protocol, then the answer is option a: B sends REJ-3, and A resends packets 3, 4, 5, 6, 7, 0 and 1. This is because the Go-Back-N protocol requires the sender to go back to the packet where the error was detected and resend all the subsequent packets, not just the erroneous one, keeping the sending window continuously full until all packets are acknowledged.